Thảo luận về các mô hình thoát nước cũng như thực trạng tính toán thoát nước đô thị hiện nay tại Việt Nam hiện nay

thanhhatran1

Senior Member
19/12/15
293
3
Theo TCXDVN 7957:2008, phương pháp tính thủy lực mạng lưới thoát nước mưa ... tại mục 4.2.6

4.2.6 Tính toán thuỷ lực hệ thống thoát nước mưa nói chung được thực hiện theo hai bước:

- Bước 1: Xác định sơ bộ kích thước công trình (bằng phương pháp cường độ giới hạn hoặc phương pháp Rational).

- Bước 2: Kiểm tra kết quả tính toán ở bước 1 bằng mô hình thuỷ lực, nếu xét thấy cần thiết thì điều chỉnh kết quả tính ở bước 1.

- Tính toán hệ thống thoát nước mưa theo phương pháp cường độ giới hạn phải tuân theo các qui định từ muc 4.2.7 đến 4.2.12.

Vấn đề đầu tiên - đấy là cường độ mưa
4.2.2 Cường độ mưa tính toán có thể xác định bằng biểu đồ hoạc công thức khác nhau, nhưng nên có đối chiếu so sánh để đảm bảo độ chính xác cao:

a. Theo biểu đồ quan hệ I – D – F (cường độ mưa-thời gian-tần suất) được lập cho từng vùng lãnh thổ.

b. Theo công thức Wenzel

(2)

Trong đó:

i- Cường độ mưa (mm/h);

T[SUB]d[/SUB] - Thời gian mưa ( phút);

f - Chu kỳ lặp lại trận mưa;

C - Hệ số phụ thuộc chu kỳ lặp lại trận mưa.

c. Theo công thức:

(3)

Trong đó:

q - Cường độ mưa (l/s.ha);

t - Thời gian dòng chảy mưa (phút);

P- Chu kỳ lặp lại trận mưa tính toán (năm);

A,C,b,n- Tham số xác định theo điều kiện mưa của địa phương, có thể chọn theo Phụ lục B; đối với vùng không có thì tham khảo vùng lân cận.

Số liệu mưa cần có chuỗi thời gian quan trắc từ 20 đến 25 năm bằng máy đo mưa tự ghi, thời gian mưa tối đa là 150 – 180 phút.

Chu kỳ lặp lại trận mưa tính toán P đối với khu vực đô thị phụ thuộc vào qui mô và tính chất công trình, xác định theo Bảng 3.

Bảng 3
Tính chất đô thị Qui mô công trình
Kênh, mương Cống chính Công nhánh khu vực
Thành phố lớn, loại I Đô thị loại II, III Các đô thị khác 10 5 2 5 2 1 2-1 1- 0,5 0,5-0,33

CHÚ THÍCH: Đối với các đô thị hay khu vực đô thị địa hình đồi núi, khi diện tích lưu vực thoát nước lớn hơn 150 ha, độ dốc địa hình lớn hơn 0,02 nếu tuyến cống chính nằm ở vệt trũng của lưu vực thì không phân biệt quy mô đô thị, giá trị P cần lấy lớn hơn quy định trong bảng, có thể chọn P bằng 10 - 20 năm dựa trên sự phân tích độ rủi ro tổng hợp và mức độ an toàn của công trình.

Đối với các khu công nghiệp tập trung, chu kỳ lặp lại trận mưa tính toán P phụ thuộc vào tính chất khu công nghiệp và được xác định theo Bảng 4.

Bảng 4
Tính chất khu công nghiệp Giá trị P
Khu công nghiệp có công nghệ bình thường Khu công nghiệp có các cơ sở sản xuất có yêu cầu đặc biệt 5 - 10 10 -20

Khi thiết kế tuyến thoát nước ở những nơi có các công trình quan trọng (như tuyến tàu điện ngầm, nhà ga xe lửa, hầm qua đường,… hoặc trên những tuyến đường giao thông quan trọng mà việc ngập nước có thể gây ra những hậu quả nghiêm trọng thì chu kỳ P lấy lớn hơn so với quy định trong Bảng 3, có thể giá trị P lấy bằng 25 năm. Đối với khu vực có địa hình bất lợi có thể lấy cao hơn (50 hoặc 100 năm) dựa trên sự phân tích tổng hợp độ rủi ro và yêu cầu an toàn.

4.2.3 Đối với thành phố lớn có nhiều trạm đo mưa cần phân tích độ tương quan của lượng mưa của các trạm để xác định hệ số phân bố mưa theo điểm và diện tích. Trong trường hợp chỉ có một trạm đo mưa thì lưu lượng tính toán cần nhân với hệ số phân bổ mưa rào n. Nếu không có tài liệu nghiên cứu ở trong nước thì có thể sử dụng biểu đồ được tổ chức khí tượngThế giới thành lập, hoặc theo qui định ở Phụ lục B.

Xem cái phụ lục B xem nào

PHỤ LỤC B


(tham khảo)

CÁC HẰNG SỐ KHÍ HẬU CỦA CÔNG THỨC CƯỜNG ĐỘ MƯA

Dạng công thức cường độ mưa:

(B1)

Trong đó:

q: Cường độ mưa (l/s.ha);

P: Chu kỳ lặp lại của mưa (năm);

t: Thời gian mưa (phút);

A, C, b, n: Hằng số khí hậu phụ thuộc vào điều kiện mưa của địa phương.

Bảng B.1 - Hằng số khí hậu trong công thức cường độ mưa của một số thành phố
TT Tên thành phố A C b n
1. Bảo Lộc 11100 0,58 30 0,95
2. Bắc Cạn 8150 0,53 27 0,87
3. Bắc Giang 7650 0,55 28 0,85
4. Bắc Quang 8860 0,57 29 0,8
5. Ba Xuyên 9430 0,55 30 0,95
6. Buôn Mê Thuột 8920 0,58 28 0,93
7. Cà Mau 9210 0,48 25 0,92
8. Cửa Tùng 2340 0,49 14 0,62
9. Đô Lương 3540 0,55 19 0,7
10. Đà Nẵng 2170 0,52 10 0,65
11. Hà Giang 4640 0,42 22 0,79
12. Hà Nam 4850 0,51 11 0,8
13. Hà Nội 5890 0,65 20 0,84
14. Hải Dương 4260 0,42 18 0,78
15. Hải Phòng 5950 0,55 21 0,82
16. Hồ Chí Minh 11650 0,58 32 0,95
17. Hòn Gai 4720 0,42 20 0,78
18. Hưng Yên 760 0,59 20 0,83
19. Hoà Bình 5500 0,45 19 0,82
20. Huế 1610 0,55 12 0,55
21. Lào Cai 6210 0,58 22 0,84
22. Lai Châu 4200 0,5 16 0,8
23. Liên Khương 9230 0,52 29 0,92
24. Móng Cái 4860 0,46 20 0,79
25. Nam Định 4320 0,55 19 0,79
26. Nha Trang 1810 0,55 12 0,65
27. Ninh Bình 4930 0,48 19 0,8
28. Phan Thiết 7070 0,55 25 0,92
29. Plây Cu 8820 0,49 29 0,92
30. Quảng Ngãi 2590 0,58 16 0,67
31. Quảng Trị 2230 0,48 15 0,62
32. Quy Nhơn 2610 0,55 14 0,68
33. Sơn La 4120 0,42 20 0,8
34. Sơn Tây 5210 0,62 19 0,82
35. Sa Pa 1720 0,5 10 0,56
36. Tây Hiếu 3360 0,54 19 0,69
37. Tam Đảo 5460 0,55 20 0,81
38. Thái Bình 5220 0,45 19 0,81
39. Thái Nguyên 7710 0,52 28 0,85
40. Thanh Hoá 3640 0,53 19 0,72
41. Trà Vinh 9150 0,53 28 0,97
42. Tuy Hoà 2820 0,48 15 0,72
43. Tuyên Quang 8670 0,55 30 0,87
44. Vân Lý 4560 0,52 21 0,79
45. Vinh 3430 0,55 20 0,69
46. Việt Trì 5830 0,55 18 0,85
47. Vĩnh Yên 5670 0,53 21 0,8
48. Yên Bái 7500 0,54 29 0,85



Bảng B.2 - Hệ số phân bố mưa rào n
Diện tích lưu vực (ha) 300 500 1000 2000 3000 4000
Hệ số phân bố mưa rào n 0,96 0,94 0,91 0,87 0,83 0,8

Nếu theo cường độ giới hạn thì rõ ràng là giá trị cường độ mưathành tưu trọn đời ... không xác định đến vấn đề biến đổi khí hậu
Nếu theo IDF thì Quan hệ giữa cường độ mưa - thời gian mưa - tần suất, các đường này được xác định riêng cho từng chu kỳ dựa trên hàm Welzel ... nghĩa là làm bài bản ... phải có số liêu mưa khá dài .... và phải móc tiền mua số liệu .... vậy thì không dại gì mà không chọn phương pháp cường độ giới hạn.​



Vấn đề thứ hai - kiểm toán kết quả bằng mô hình thủy lực -- kiểm toán theo mô hình thủy lực thì chọn mô hình nào? Hiện nay được biết phần lớn các dự án thoát nước không sử dụng mô hình thủy lực ... có một vài đơn vị thì đang đang sử dụng SWMM --- nhưng tính pháp lý của mô hình này chưa rõ ràng - mặc dù là mô hình tiên tiến của Hoa Kỳ - nhưng phần lớn các sở xây dựng các tỉnh mù mịt

Cuối tuần tạm khêu gợi vậy đã
 

tamxuanpham

Thành viên chính thức
7/3/14
324
21
Thì cứ sử dụng SWMM cho thoát nước đô thị, HEC-RAS chi kênh rạch có sao nhỉ?
Còn cắm đầu cắm cổ tự tạo mô hình (Hydraulic Modeling) riêng dù chúng ta sẽ có được một sự hiểu biết đầy đủ về hành vi thủy lực của hệ thống thoát nước, nhưng hành trình hơi bị gian nan.
 

hoangdung

Moderator
Thành viên BQT
2/4/13
219
24
Hiện nay ngay cả nước ngoài chứ không chỉ Việt Nam nhầm lẫn lung tung xà beng Mô Hình với Phương Pháp, dẫn đến tiêu chuẩn thoát nước cũng lung tung xà beng - thôi thì copy nguyên văn để đây cho mọi người ngâm cái đã rồi chém sau

https://www.vanharen.net/blog/van-ha...e-terminology/

There is a lot of confusion regarding the use and meaning of the terms ‘standard’, ‘best practice’, ‘body of knowledge’, ‘framework’, ‘guidance’, ‘method’, ‘model’ etc. In order to promote and establish a consistent use of these terms within VHP publications we have developed this document. It is, of course, based on a ‘best practice’ approach and is the result of input from various stakeholders.

A model is the presentation in schematic form, often in a simplified way, of an existing or future state or situation. The modelling technique determines the way in which the situation is represented in a schematic way. Popular modelling techniques are: process model, workflow model, life cycle model.

A method is a systematic approach to achieve a specific result or goal, and offers a description in a cohesive and (scientific) consistent way of the approach that leads to the desired result/ goal. Minimally a method consists of a way of thinking and a way of working. Possible additional components of a method are: management model(s), presentation model(s), support model(s) (prescriptions, instructions, tips, examples, etc.), based on the modelling techniques mentioned above. The meanings of the terms ‘practice’ and ‘model’ are much broader than the term ‘method’.

Tiếp đến nữa thì đọc qua cái này
https://www.hydrocad.net/
HydroCAD is a Computer Aided Design tool used by Civil Engineers for modeling stormwater runoff. HydroCAD provides a wide range of commonly used drainage calculations including:
SCS, NRCS, SBUH runoff hydrology
Rational Method with automatic IDF curves
Use local rainfall or the predefined rainfall library
Unlimited hydrograph points
Hydrograph routing through ponds & reaches
Coupled ponds with automatic tailwater
Automatic hydraulics and culvert calculations
Advanced flow simulations including pumps and float valves
Progressive dam breach simulations
Automatic pond storage calculations, including embedded storage chambers
Automatic layout and modeling of underground storage systems
Land-use analysis and pollutant loading calculations
Built-in CAD watershed import
Easy management and reporting of multiple rainfall events
Runs on any Windows PC - No other CAD software required

HydroCAD is ideal for studies using the TR-20, TR-55, or SBUH methods. (Please visit the Hydrology Library for background information.) HydroCAD provides a wide range of standard H&H techniques in an easy-to-use graphical form, managed by the on-screen routing diagram we pioneered in 1986. Complete details here.

HydroCAD can speed up your hydrology and hydraulics ten-fold, at an unbeatable cost. Try it yourself with our free HydroCAD Sampler.
 

hoangdung

Moderator
Thành viên BQT
2/4/13
219
24
Để hy vọng mọi người hiểu rõ thế nào là Mô Hình thế nào là Phương Pháp

Lỡ copy thì hầu copy luôn - phòng đứt cáp dạo này trục trặc

https://stormwater.pca.state.mn.us/i...ecting_a_model

Available stormwater models and selecting a model

Hydrologic, hydraulic, and water quality models all have different purposes and will provide different information. The tables shown at the bottom of this page summarize some of the commonly used modeling software and modeling functions and the main purpose for which they were developed (NOTE: the information in these tables can be downloaded as an Excel file). The tables show the relative levels of complexity of necessary input data, indicate whether the model can complete a continuous analysis or is event based, list whether the model is in the public domain, and for hydraulic models indicate whether unsteady flow calculations can be conducted. For water quality models, the tables indicate whether the model is a receiving waters model, a loading model, or a BMP analysis model. The following definitions apply to the model functions.
  • Rainfall-Runoff Calculation Tool: peak flow, runoff volume, and hydrograph functions, only. More complex modeling should utilize hydrologic modeling which incorporate rainfall-runoff functions.
  • Hydrologic: includes rainfall-runoff simulation plus reservoir/channel routing.
  • Hydraulic: water surface profiles, flow rates, and flow velocities through waterways, structures and pipes. Models that include Green Infrastructure typically also assess how the BMPs managage the water through inflow, infiltration, evapotranspiration, storage and discharge.
  • Combined Hydrologic & Hydraulic: rainfall-runoff results become input into hydraulic calculations.
  • Water Quality: pollutant loading to surface waters or pollutant removal in a BMP.
  • BMP Calculators: spreadsheets that predict BMP performance, only.
Defining Model Objectives and Selecting a Stormwater Model


Environmental modeling, including stormwater and water quality modeling, is complex given the purpose is to mathematically predict natural processes (USEPA, 2009). Models range from simple spreadsheets that predict a single process such as the runoff from a single storm, to complex simulations that predict multiple, inter-related processes including performance of multiple BMPs. A greater amount of uncertainty is inherent in the more complex models, which results in more complexity in model calibration (WEF, 2012). For example, estimating peak runoff rates is a different problem than estimating the peak elevation of a water body and could require the use of a different model. A model able to estimate phosphorus loading from a network of detention ponds may not be able to model the phosphorus loading from an infiltration pond.

Therefore it is important that modelers select a stormwater modeling tool that is based on both modeling objectives and available resources. The USEPA recommends that the first step in development of a model is to define the objectives (USEPA, 2009). When defining the modeling objectives, the modelers and decision-makers should consider the following (WEF, 2012):
  • Regulatory compliance: is the model required for regulatory compliance? Which models are accepted by the regulatory agency?
  • Hydrologic process: is the goal to model a single storm event or continuous rainfall? Should the model incorporate infiltration, evaporation, transpiration, abstraction, and other physical processes that reduce the volume of runoff? Is the model required to predict large storm events (for flood control), small storm events (for water quality predictions), or both?
  • Land use: is the model required for large rural/agricultural catchments or small urban catchments?
  • Area to be modeled: will the model be required to predict stormwater for individual blocks? Or is a larger catchment scale acceptable?
  • Intended use: is the intended use for planning purposes, engineering/design, or operational performance?
  • Model complexity: will a simple model be sufficient?
  • Modeler experience: what is the model-specific expertise of current staff? Is there budget to hire an expert?
The actual process of selecting a model is likely to be an iterative process of model evaluation, adjustments to objectives and/or costs, re-evaluation, and ultimately model selection. Potentially, modelers may select multiple models to meet the objectives of the study. For example one model may be best for hydrology and hydraulics, while another may be best for BMP performance. In these circumstances the modelers should investigate the ability of the models to be linked (USEPA, 2009).



Summary of Common Stormwater Models


The following section describes the most common stormwater models used by stormwater professionals. Use the hyperlinks for additional information on these models.

Rational method

The Rational Method is a simple hydrologic calculation of peak flow based on drainage area, rainfall intensity, and a non-dimensional runoff coefficient. The peak flow is calculated as the rainfall intensity in inches per hour multiplied by the runoff coefficient and the drainage area in acres. The peak flow, Q, is calculated in cubic feet per second (cfs) as Q = CiA where C is the runoff coefficient, i is the rainfall intensity, and A is the drainage area. A conversion factor of 1.008 is necessary to convert acre-inches per hour to cfs, but this is typically not used. This method is best used only for simple approximations of peak flow from small watersheds.

HEC-HMS

HEC-HMS is a hydrologic rainfall-runoff model developed by the U.S. Army Corps of Engineers that is based on the rainfall-runoff prediction originally developed and released as HEC-1. HEC-HMS is used to compute runoff hydrographs for a network of watersheds. The model evaluates infiltration losses, transforms precipitation into runoff hydrographs, and routes hydrographs through open channel routing. A variety of calculation methods can be selected including SCS curve number or Green and Ampt infiltration; Clark, Snyder or SCS unit hydrograph methods; and Muskingum, Puls, or lag routing methods. Precipitation inputs can be evaluated using a number of historical or synthetic methods and one evapotranspiration method. HEC-HMS is used in combination with HEC-RAS for calculation of both the hydrology and hydraulics of a stormwater system or network.

TR-20

Natural Resources Conservation Service Technical Release No. 20 (TR-20): Computer Program for Project Formulation Hydrology was developed by the hydrology branch of the U.S.D.A. Soil Conservation Service in 1964. It was recently updated to allow users to import Atlas 14 precipitation data available from NOAA.

WinTR-20 is a single event watershed scale runoff and routing (hydrologic) model that is best suited to predict stream flows in large watersheds. It computes direct runoff and develops hydrographs resulting from any synthetic or natural rainstorm. Developed hydrographs are routed through stream and valley reaches as well as through reservoirs. Hydrographs are combined from tributaries with those on the main stream. Branching flow (diversion), and baseflow can also be accommodated. WinTR-20 may be used to evaluate flooding problems, alternatives for flood control (reservoirs, channel modification, and diversion), and impacts of changing land use on the hydrologic response of watersheds. A new routine has been added to the program that allows the user to import NOAA Atlas 14 rainfall data for site-specific applications. The rainfall-frequency data will be used to develop site-specific rainfall distributions. The NOAA 14 text files for selected states are available in the Support Materials for downloading and use in WinTR-20 Version 1.11. The NOAA 14 text files and supporting GIS files are packaged in a zip file for each state.

Win TR-55

Technical Release 55 (TR-55; Urban Hydrology for Small Watersheds) was developed by the U.S.D.A. Soil Conservation Service, now the Natural Resources Conservation Service (NRCS), in 1975 as a simplified procedure to calculate storm runoff volume, peak rate of discharge, hydrographs and storage volumes in small urban watersheds. In 1998, Technical Release 55 and the computer software were revised to what is now called WinTR-55. The changes in this revised version of TR-55 include: upgraded source code to Visual Basic, changed philosophy of data input, development of a Windows interface and output post-processor, enhanced hydrograph-generation capability of the software and flood routing hydrographs through stream reaches and reservoirs. WinTR-55 is a single-event rainfall-runoff small watershed hydrologic model. The model is an input/output interface which runs WinTR-20 in the background to generate, route and add hydrographs. The WinTR-55 generates hydrographs from both urban and agricultural areas at selected points along the stream system. Hydrographs are routed downstream through channels and/or reservoirs. Multiple sub-areas can be modeled within the watershed. A rainfall-runoff analysis can be performed on up to ten sub-areas and up to ten reaches. The total drainage area modeled cannot exceed 25 square miles.

HEC-RAS

HEC-RAS is a river hydraulics model developed by the U.S. Army Corps of Engineers to compute one-dimensional water surface profiles for steady or unsteady flow. HEC-RAS is an updated version of HEC-2. Computation of steady flow water surface profiles is intended for flood plain studies and floodway encroachment evaluations. HEC-RAS uses the solution of the one-dimensional energy equation with energy losses evaluated for friction and contraction and expansion losses in order to compute water surface profiles. In areas with rapidly varied water surface profiles, HEC-RAS uses the solution of the momentum equation. Unsteady flow simulation can evaluate subcritical flow regimes as well as mixed flow regimes including supercritical, hydraulic jumps, and draw downs. Sediment transport calculation capability will be added in future versions of the model. The HEC-RAS program is available to the public from the U.S. Army Corps of Engineers. HEC-RAS utilizes the hydrologic results that are developed in HEC-HMS.

WSPRO

WSPRO is a hydraulic model for water surface profile computations developed by the U.S. Geological Survey. The model evaluates one-dimensional water surface profiles for systems with gradually varied, steady flow. The open channel calculations are conducted using backwater techniques and energy balancing methods. Single opening bridges use the orifice flow equation and flow through culverts is computed using a regression equation at the inlet and an energy balance at the outlet. The WSPRO program is available to the public and can be downloaded from the U.S. Geological Survey.


CULVERTMASTER

CulvertMaster is a hydraulic analysis program for culvert design. The model uses the U.S. Federal Highway Administration Hydraulic Design of Highway Culverts methodology to provide estimates for headwater elevation, hydraulic grade lines, discharge, and culvert sizing. Rainfall and watershed analysis using the SCS Method or Rational Method can be incorporated if the peak flow rate is not known. CulvertMaster is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.


FLOWMASTER

FlowMaster is a hydraulic analysis program used for the design and analysis of open channels, pressure pipes, inlets, gutters, weirs, and orifices. Mannings, Hasen-Williams, Kutter, Darcy- Weisbach, or Colebrook-White equations are used in the calculations. FlowMaster is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.

HydroCAD

HydroCAD is a computer aided design program for modeling the hydrology and hydraulics of stormwater runoff. Runoff hydrographs are computed using the SCS runoff equation and the SCS dimensionless unit hydrograph. For the hydrologic computations, there is no provision for recovery of initial abstraction or infiltration during periods of no rainfall within an event. The program computes runoff hydrographs, routes flows through channel reaches and reservoirs, and combines hydrographs at confluences of the watershed stream system. HydroCAD has the ability to simulate backwater conditions by allowing the user to define the backwater elevation prior to simulating a rainfall event. HydroCAD is a proprietary model and can be obtained from HydroCAD Software Solutions LLC.

PondPack

PondPack is a program for modeling and design of the hydrology and hydraulics of storm water runoff and pond networks. Rainfall analyses can be conducted using a number of synthetic or historic storm events using methods such as SCS rainfall distributions, intensity-duration-frequency curves, or recorded rainfall data. Infiltration and runoff can be computed using the SCS curve number method or the Green and Ampt or Horton infiltration methods. Hydrographs are computed using the SCS Method or the Rational Method. Channel routing is conducted using the Muskingun, translation, or Modified Puls methods. Outlet calculations can be performed for outlets such as weirs, culverts, orifices, and risers. The program can assist in the determination of pond sizes. PondPack is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.


SWMM-Based programs (SWMM5, PC-SWMM, InfoSWMM, MikeUrban)

SWMM-Based Programs SWMM is a hydraulic and hydrologic modeling system that also has a water quality component. Please see the full description above for more details on the model. The Storm Water Management Model (SWMM) was originally developed for the Environmental Protection Agency (EPA) in 1971. SWMM is a dynamic rainfall-runoff and water quality simulation model, primarily but not exclusively for urban areas, for single-event or long-term (continuous) simulation. Version 5 of SWMM was developed in 2005 and has been updated multiple times since. The Storm Water Management Model (SWMM) is a comprehensive computer model for analysis of quantity and quality problems associated with urban runoff. Both single-event and continuous simulation can be performed on catchments having storm sewers, or combined sewers and natural drainage, for prediction of flows, stages and pollutant concentrations. Extran Block solves complete dynamic flow routing equations (St. Venant equations) for accurate simulation of backwater, looped connections, surcharging, and pressure flow. A modeler can simulate all aspects of the urban hydrologic and quality cycles, including rainfall, snow melt, surface and subsurface runoff, flow routing through drainage network, storage and treatment. Statistical analyses can be performed on long-term precipitation data and on output from continuous simulation. SWMM can be used for planning and design. Planning mode is used for an overall assessment of urban runoff problem or proposed abatement options. Current update of SWMM includes the capability to model the flow rate, flow depth and quality of Low Impact Development (LID) controls, including permeable pavement, rain gardens, green roofs, street planters, rain barrels, infiltration trenches, and vegetative swales The SWMM program is available to the public. The proprietary shells, PC-SWMM, InfoSWMM, and Mike Urban, provide the basic computations of EPASWMM with a graphic user interface, additional tools, and some additional computational capabilities.

XPSWMM

XPSWMM is a propriety model that originally began as a SWMM based program. The model developer has developed many upgrades that are independent of the USEPA upgrades to SWMM. Because of these upgrades the two software platforms are no longer interchangeable. XP SWMM does have a function that allows model data to be exported in SWMM format. Comparison of model results between the two softwares will result in similar, but not identical, results.

XP SWMM’s hydrologic and hydraulic capabilities includes modeling of floodplains, river systems, stormwater systems, BMPs (including green infrastructure), watersheds, sanitary sewers, and combined sewers. Pollutant modeling capabilities include pollutant and sediment loading and transport as well as pollutant removal for a suite of BMPs. XP-SWMM is available from XP Solutions.


WinSLAMM

The Source Loading and Management Model is a stormwater quality model developed for the USGS by John Voorhees and Robert Pitt for evaluation of nonpoint pollution in urban areas. The model is based on field observations of grass swales, wet detention ponds, porous pavement, filter strips, cisterns and rain barrels, hydrodynamic settling devices, rain gardens/biofilters and street sweeping, as either other source area or outfall control practices. The focus of the model is on small storm hydrology and particulate washoff. The WinSLAMM model may be obtained from PV & Associates. Wisconsin data files for input into SLAMM may be obtained from the U.S. Geological Survey, and the model provides an extensive set of rainfall, runoff and particulate solids and other pollutant files developed from the National Stormwater Quality Data Base for most urban areas in the county.

The graphical interface allows users to define both source area and drainage system stormwater control practices using a drag-and-drop interface, and the program and web site provides extensive program help and stormwater quality references.

P8

P8 - Program for Predicting Polluting Particle Passage through Pits, Puddles & Ponds, is a physically-based stormwater quality model developed by William Walker to predict the generation and transport of stormwater runoff pollutants in urban watersheds. The model simulates runoff and pollutant transport for a maximum of 24 watersheds, 24 stormwater best management practices (BMPs), 5 particle size classes, and 10 water quality components. The model simulates pollutant transport and removal in a variety of BMPs including swales, buffer strips, detention ponds (dry, wet and extended), flow splitters, and infiltration basins (offline and online). Model simulations are driven by a continuous hourly rainfall time series. P8 has been designed to require a minimum of site-specific data, which are expressed in terminology familiar to most engineers and planners. An extensive user interface providing interactive operation, spreadsheet-like menus, help screens and high resolution graphics facilitate model use.


BASINS

The Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) model is a multipurpose surface water environmental analysis system developed by the U.S. Environmental Protection Agency’s (EPA’s) Office of Water. The model was originally introduced in 1996 and has had subsequent releases in 1998 and 2001. BASINS allows for the assessment of large amounts of point and non-point source data in a format that is easy to use and understand. BASINS incorporates a number of model interfaces that it uses to assess water quality at selected stream sites or throughout the watershed. These model interfaces include:
  • QUAL2E: A water quality and eutrophication model
  • WinHSPF: A watershed scale model for estimating in-stream concentrations resulting from loadings from point and non-point sources
  • SWAT: A physical based, watershed scale model that was developed to predict the impacts of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land uses and management conditions over long periods of time.
  • PLOAD: A pollutant loading model.
PONDNET


The PONDNET model (Walker, 1987) is an empirical model developed to evaluate flow and phosphorous routing in Pond Networks. The following input parameters are defined by the user in evaluating the water quality performance of a pond: watershed area (acres), runoff coefficient, pond surface area (acres), pond mean depth (feet), period length (years), period precipitation (inches) and phosphorous concentrations (ppb). The spreadsheet is designed so that the phosphorous removal of multiple ponds in series can be evaluated.

WiLMS

The Wisconsin Lake Modeling Suite (WiLMS) is a screening level land use management/lake water quality evaluation tool developed by the Wisconsin Department of Natural Resources. It is a spreadsheet of thirteen lake model equations used to predict the total phosphorus (TP) concentration in a lake. TP loads can be entered either as point sources or by entering export coefficients for land uses. WiLMS can be downloaded for free at the Wisconsin DNR Web page.

Bathtub

Bathtub is an empirical model of reservoir eutrophication developed by the U.S. Army Corps of Engineers. Single basins can be modeled, in addition to a network of basins that interact with one another. The model uses steady-state water and nutrient balance calculations in a spatially segmented hydraulic network, which accounts for advective and diffusive transport and nutrient sedimentation.

WASP

WASP, Water Quality Analysis Simulation Program, is a model developed by the U.S. EPA to evaluate the fate and transport of contaminants in surface waters such as lakes and ponds. The model evaluates advection, dispersion, mass loading, and boundary exchange in one, two, or three dimensions. A variety of pollutants can be modeled with this program including nutrients, dissolved oxygen, BOD, algae, organic chemicals, metals, pathogens, and temperature.

SUSTAIN

SUSTAIN (System for Urban Stormwater Treatment and Analysis Integration) was developed by the USEPA to assist stormwater professionals in developing and implementing plans for stormwater flow and pollutant controls on a watershed scale. SUSTAIN contains seven modules that integrate with ArcGIS. Hydrology, hydraulics, and pollutant loading are computed using EPASWMM, Version 5. Sediment transport is based on HSPF. Modules include:
  • Framework manager
  • BMP siting tool
  • Land simulation module
  • BMP simulation module
  • Conveyance simulation
  • BMP optimization
  • Post-processor
MIDS Calculator

The MIDS Calculator was developed by the MPCA as an Excel-based stormwater quality tool to predict the annual pollutant removal performance of low impact development (LID) BMPs. The calculator will compute the volume reduction associated with infiltration practices plus the TSS and TP reductions for both LID and traditional BMPs, including permeable pavements, green roofs, bioretention, bioretention with underdrain (biofiltration), infiltration basin, tree trench, tree trench with underdrain, swale side slope, swale channels, swales with underdrains, wet swale, cistern/reuse, sand filter, constructed wetland and constructed stormwater pond.

STEPL

The Spreadsheet Tool for Estimating Pollutant Load (STEPL) was developed by the USEPA to calculate nutrient and sediment loads from different rural land uses and BMPs on a watershed scale. STEPL provides a user-friendly interface to create a customized spreadsheet-based model in Microsoft (MS) Excel. It computes watershed surface runoff; nutrient loads, including nitrogen, phosphorus, and 5-day biological oxygen demand (BOD5); and sediment delivery. The annual sediment load (sheet and rill erosion only) is calculated based on the Universal Soil Loss Equation (USLE) and the sediment delivery ratio. The sediment and pollutant load reductions that result from the implementation of BMPs are computed using the known BMP efficiencies.

Virginia Model


USEPA National Stormwater Calculator

The National Stormwater Calculator is a tool developed by the USEPA for computing small site hydrology for any location within the U.S. (www.epa.gov/nrmrl/wswrd/wq/models/swc/). It estimates the amount of stormwater runoff generated from a site under different development and control scenarios over a long term period of historical rainfall. The analysis takes into account local soil conditions, slope, land cover and meteorology. Different types of low impact development (LID) practices (also known as green infrastructure) can be employed to help capture and retain rainfall on-site. Future climate change scenarios taken from internationally recognized climate change projections can also be considered. The calculator’s primary focus is informing site developers and property owners on how well they can meet a desired stormwater retention target.
 

thanhhatran1

Senior Member
19/12/15
293
3
Có vè hoangdung không hiểu ý mình nói ... bản chất thoát nước xưa nay gồm 3 yếu tố:
- Mưa: mưa như thế nào ...
- Tập trung nước bề mặt
- Chảy trong hệ thống

Tách bạch kiểu chuyên ngành thì có thủy văn và thủy lực, thủy văn cung cấp đầu vào cho thủy lực. Ý mình nói là nói cái tiêu chuẩn rất ấm ớ Việt gian ...
- Sơ bộ thì độ cương giới hạn (hoặc tương tự)
- Xuất hàng thì dùng mô hình thủy lực ... nếu hàng xuất ra mà không đạt thì quay lại bước sơ bộ (sửa sơ bộ)

Người nào đã sử dụng phần mềm MIKE URBAN, SWMM, HEC-HMS hoặc TUFLOW sẽ hiểu các phần mềm này là tập hợp rất nhiều mô hình ... tuy nhiên một mô hình tính toán thoát nước thì bao gồm 2 mô hình: mô hình thủy văn và mô hình thủy lực ... thủy văn cung cấp cho bạn số lượng nước (dòng chảy) và thủy lực như thế nào nó chảy trong hệ thống của bạn.

Thủy văn thì lại liên quan đến mưa, với phương pháp tương tự thì dùng IDF .... với SWMM thì dùng mưa theo thời gian

Nghĩa là tiêu chuẩn ấm ớ
 

thanhhatran1

Senior Member
19/12/15
293
3
hoangdung nói:
Để hy vọng mọi người hiểu rõ thế nào là Mô Hình thế nào là Phương Pháp

Lỡ copy thì hầu copy luôn - phòng đứt cáp dạo này trục trặc

https://stormwater.pca.state.mn.us/i...ecting_a_model

Available stormwater models and selecting a model

Hydrologic, hydraulic, and water quality models all have different purposes and will provide different information. The tables shown at the bottom of this page summarize some of the commonly used modeling software and modeling functions and the main purpose for which they were developed (NOTE: the information in these tables can be downloaded as an Excel file). The tables show the relative levels of complexity of necessary input data, indicate whether the model can complete a continuous analysis or is event based, list whether the model is in the public domain, and for hydraulic models indicate whether unsteady flow calculations can be conducted. For water quality models, the tables indicate whether the model is a receiving waters model, a loading model, or a BMP analysis model. The following definitions apply to the model functions.
  • Rainfall-Runoff Calculation Tool: peak flow, runoff volume, and hydrograph functions, only. More complex modeling should utilize hydrologic modeling which incorporate rainfall-runoff functions.
  • Hydrologic: includes rainfall-runoff simulation plus reservoir/channel routing.
  • Hydraulic: water surface profiles, flow rates, and flow velocities through waterways, structures and pipes. Models that include Green Infrastructure typically also assess how the BMPs managage the water through inflow, infiltration, evapotranspiration, storage and discharge.
  • Combined Hydrologic & Hydraulic: rainfall-runoff results become input into hydraulic calculations.
  • Water Quality: pollutant loading to surface waters or pollutant removal in a BMP.
  • BMP Calculators: spreadsheets that predict BMP performance, only.
Defining Model Objectives and Selecting a Stormwater Model


Environmental modeling, including stormwater and water quality modeling, is complex given the purpose is to mathematically predict natural processes (USEPA, 2009). Models range from simple spreadsheets that predict a single process such as the runoff from a single storm, to complex simulations that predict multiple, inter-related processes including performance of multiple BMPs. A greater amount of uncertainty is inherent in the more complex models, which results in more complexity in model calibration (WEF, 2012). For example, estimating peak runoff rates is a different problem than estimating the peak elevation of a water body and could require the use of a different model. A model able to estimate phosphorus loading from a network of detention ponds may not be able to model the phosphorus loading from an infiltration pond.

Therefore it is important that modelers select a stormwater modeling tool that is based on both modeling objectives and available resources. The USEPA recommends that the first step in development of a model is to define the objectives (USEPA, 2009). When defining the modeling objectives, the modelers and decision-makers should consider the following (WEF, 2012):
  • Regulatory compliance: is the model required for regulatory compliance? Which models are accepted by the regulatory agency?
  • Hydrologic process: is the goal to model a single storm event or continuous rainfall? Should the model incorporate infiltration, evaporation, transpiration, abstraction, and other physical processes that reduce the volume of runoff? Is the model required to predict large storm events (for flood control), small storm events (for water quality predictions), or both?
  • Land use: is the model required for large rural/agricultural catchments or small urban catchments?
  • Area to be modeled: will the model be required to predict stormwater for individual blocks? Or is a larger catchment scale acceptable?
  • Intended use: is the intended use for planning purposes, engineering/design, or operational performance?
  • Model complexity: will a simple model be sufficient?
  • Modeler experience: what is the model-specific expertise of current staff? Is there budget to hire an expert?
The actual process of selecting a model is likely to be an iterative process of model evaluation, adjustments to objectives and/or costs, re-evaluation, and ultimately model selection. Potentially, modelers may select multiple models to meet the objectives of the study. For example one model may be best for hydrology and hydraulics, while another may be best for BMP performance. In these circumstances the modelers should investigate the ability of the models to be linked (USEPA, 2009).



Summary of Common Stormwater Models


The following section describes the most common stormwater models used by stormwater professionals. Use the hyperlinks for additional information on these models.

Rational method

The Rational Method is a simple hydrologic calculation of peak flow based on drainage area, rainfall intensity, and a non-dimensional runoff coefficient. The peak flow is calculated as the rainfall intensity in inches per hour multiplied by the runoff coefficient and the drainage area in acres. The peak flow, Q, is calculated in cubic feet per second (cfs) as Q = CiA where C is the runoff coefficient, i is the rainfall intensity, and A is the drainage area. A conversion factor of 1.008 is necessary to convert acre-inches per hour to cfs, but this is typically not used. This method is best used only for simple approximations of peak flow from small watersheds.

HEC-HMS

HEC-HMS is a hydrologic rainfall-runoff model developed by the U.S. Army Corps of Engineers that is based on the rainfall-runoff prediction originally developed and released as HEC-1. HEC-HMS is used to compute runoff hydrographs for a network of watersheds. The model evaluates infiltration losses, transforms precipitation into runoff hydrographs, and routes hydrographs through open channel routing. A variety of calculation methods can be selected including SCS curve number or Green and Ampt infiltration; Clark, Snyder or SCS unit hydrograph methods; and Muskingum, Puls, or lag routing methods. Precipitation inputs can be evaluated using a number of historical or synthetic methods and one evapotranspiration method. HEC-HMS is used in combination with HEC-RAS for calculation of both the hydrology and hydraulics of a stormwater system or network.

TR-20

Natural Resources Conservation Service Technical Release No. 20 (TR-20): Computer Program for Project Formulation Hydrology was developed by the hydrology branch of the U.S.D.A. Soil Conservation Service in 1964. It was recently updated to allow users to import Atlas 14 precipitation data available from NOAA.

WinTR-20 is a single event watershed scale runoff and routing (hydrologic) model that is best suited to predict stream flows in large watersheds. It computes direct runoff and develops hydrographs resulting from any synthetic or natural rainstorm. Developed hydrographs are routed through stream and valley reaches as well as through reservoirs. Hydrographs are combined from tributaries with those on the main stream. Branching flow (diversion), and baseflow can also be accommodated. WinTR-20 may be used to evaluate flooding problems, alternatives for flood control (reservoirs, channel modification, and diversion), and impacts of changing land use on the hydrologic response of watersheds. A new routine has been added to the program that allows the user to import NOAA Atlas 14 rainfall data for site-specific applications. The rainfall-frequency data will be used to develop site-specific rainfall distributions. The NOAA 14 text files for selected states are available in the Support Materials for downloading and use in WinTR-20 Version 1.11. The NOAA 14 text files and supporting GIS files are packaged in a zip file for each state.

Win TR-55

Technical Release 55 (TR-55; Urban Hydrology for Small Watersheds) was developed by the U.S.D.A. Soil Conservation Service, now the Natural Resources Conservation Service (NRCS), in 1975 as a simplified procedure to calculate storm runoff volume, peak rate of discharge, hydrographs and storage volumes in small urban watersheds. In 1998, Technical Release 55 and the computer software were revised to what is now called WinTR-55. The changes in this revised version of TR-55 include: upgraded source code to Visual Basic, changed philosophy of data input, development of a Windows interface and output post-processor, enhanced hydrograph-generation capability of the software and flood routing hydrographs through stream reaches and reservoirs. WinTR-55 is a single-event rainfall-runoff small watershed hydrologic model. The model is an input/output interface which runs WinTR-20 in the background to generate, route and add hydrographs. The WinTR-55 generates hydrographs from both urban and agricultural areas at selected points along the stream system. Hydrographs are routed downstream through channels and/or reservoirs. Multiple sub-areas can be modeled within the watershed. A rainfall-runoff analysis can be performed on up to ten sub-areas and up to ten reaches. The total drainage area modeled cannot exceed 25 square miles.

HEC-RAS

HEC-RAS is a river hydraulics model developed by the U.S. Army Corps of Engineers to compute one-dimensional water surface profiles for steady or unsteady flow. HEC-RAS is an updated version of HEC-2. Computation of steady flow water surface profiles is intended for flood plain studies and floodway encroachment evaluations. HEC-RAS uses the solution of the one-dimensional energy equation with energy losses evaluated for friction and contraction and expansion losses in order to compute water surface profiles. In areas with rapidly varied water surface profiles, HEC-RAS uses the solution of the momentum equation. Unsteady flow simulation can evaluate subcritical flow regimes as well as mixed flow regimes including supercritical, hydraulic jumps, and draw downs. Sediment transport calculation capability will be added in future versions of the model. The HEC-RAS program is available to the public from the U.S. Army Corps of Engineers. HEC-RAS utilizes the hydrologic results that are developed in HEC-HMS.

WSPRO

WSPRO is a hydraulic model for water surface profile computations developed by the U.S. Geological Survey. The model evaluates one-dimensional water surface profiles for systems with gradually varied, steady flow. The open channel calculations are conducted using backwater techniques and energy balancing methods. Single opening bridges use the orifice flow equation and flow through culverts is computed using a regression equation at the inlet and an energy balance at the outlet. The WSPRO program is available to the public and can be downloaded from the U.S. Geological Survey.


CULVERTMASTER

CulvertMaster is a hydraulic analysis program for culvert design. The model uses the U.S. Federal Highway Administration Hydraulic Design of Highway Culverts methodology to provide estimates for headwater elevation, hydraulic grade lines, discharge, and culvert sizing. Rainfall and watershed analysis using the SCS Method or Rational Method can be incorporated if the peak flow rate is not known. CulvertMaster is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.


FLOWMASTER

FlowMaster is a hydraulic analysis program used for the design and analysis of open channels, pressure pipes, inlets, gutters, weirs, and orifices. Mannings, Hasen-Williams, Kutter, Darcy- Weisbach, or Colebrook-White equations are used in the calculations. FlowMaster is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.

HydroCAD

HydroCAD is a computer aided design program for modeling the hydrology and hydraulics of stormwater runoff. Runoff hydrographs are computed using the SCS runoff equation and the SCS dimensionless unit hydrograph. For the hydrologic computations, there is no provision for recovery of initial abstraction or infiltration during periods of no rainfall within an event. The program computes runoff hydrographs, routes flows through channel reaches and reservoirs, and combines hydrographs at confluences of the watershed stream system. HydroCAD has the ability to simulate backwater conditions by allowing the user to define the backwater elevation prior to simulating a rainfall event. HydroCAD is a proprietary model and can be obtained from HydroCAD Software Solutions LLC.

PondPack

PondPack is a program for modeling and design of the hydrology and hydraulics of storm water runoff and pond networks. Rainfall analyses can be conducted using a number of synthetic or historic storm events using methods such as SCS rainfall distributions, intensity-duration-frequency curves, or recorded rainfall data. Infiltration and runoff can be computed using the SCS curve number method or the Green and Ampt or Horton infiltration methods. Hydrographs are computed using the SCS Method or the Rational Method. Channel routing is conducted using the Muskingun, translation, or Modified Puls methods. Outlet calculations can be performed for outlets such as weirs, culverts, orifices, and risers. The program can assist in the determination of pond sizes. PondPack is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.


SWMM-Based programs (SWMM5, PC-SWMM, InfoSWMM, MikeUrban)

SWMM-Based Programs SWMM is a hydraulic and hydrologic modeling system that also has a water quality component. Please see the full description above for more details on the model. The Storm Water Management Model (SWMM) was originally developed for the Environmental Protection Agency (EPA) in 1971. SWMM is a dynamic rainfall-runoff and water quality simulation model, primarily but not exclusively for urban areas, for single-event or long-term (continuous) simulation. Version 5 of SWMM was developed in 2005 and has been updated multiple times since. The Storm Water Management Model (SWMM) is a comprehensive computer model for analysis of quantity and quality problems associated with urban runoff. Both single-event and continuous simulation can be performed on catchments having storm sewers, or combined sewers and natural drainage, for prediction of flows, stages and pollutant concentrations. Extran Block solves complete dynamic flow routing equations (St. Venant equations) for accurate simulation of backwater, looped connections, surcharging, and pressure flow. A modeler can simulate all aspects of the urban hydrologic and quality cycles, including rainfall, snow melt, surface and subsurface runoff, flow routing through drainage network, storage and treatment. Statistical analyses can be performed on long-term precipitation data and on output from continuous simulation. SWMM can be used for planning and design. Planning mode is used for an overall assessment of urban runoff problem or proposed abatement options. Current update of SWMM includes the capability to model the flow rate, flow depth and quality of Low Impact Development (LID) controls, including permeable pavement, rain gardens, green roofs, street planters, rain barrels, infiltration trenches, and vegetative swales The SWMM program is available to the public. The proprietary shells, PC-SWMM, InfoSWMM, and Mike Urban, provide the basic computations of EPASWMM with a graphic user interface, additional tools, and some additional computational capabilities.

XPSWMM

XPSWMM is a propriety model that originally began as a SWMM based program. The model developer has developed many upgrades that are independent of the USEPA upgrades to SWMM. Because of these upgrades the two software platforms are no longer interchangeable. XP SWMM does have a function that allows model data to be exported in SWMM format. Comparison of model results between the two softwares will result in similar, but not identical, results.

XP SWMM’s hydrologic and hydraulic capabilities includes modeling of floodplains, river systems, stormwater systems, BMPs (including green infrastructure), watersheds, sanitary sewers, and combined sewers. Pollutant modeling capabilities include pollutant and sediment loading and transport as well as pollutant removal for a suite of BMPs. XP-SWMM is available from XP Solutions.


WinSLAMM

The Source Loading and Management Model is a stormwater quality model developed for the USGS by John Voorhees and Robert Pitt for evaluation of nonpoint pollution in urban areas. The model is based on field observations of grass swales, wet detention ponds, porous pavement, filter strips, cisterns and rain barrels, hydrodynamic settling devices, rain gardens/biofilters and street sweeping, as either other source area or outfall control practices. The focus of the model is on small storm hydrology and particulate washoff. The WinSLAMM model may be obtained from PV & Associates. Wisconsin data files for input into SLAMM may be obtained from the U.S. Geological Survey, and the model provides an extensive set of rainfall, runoff and particulate solids and other pollutant files developed from the National Stormwater Quality Data Base for most urban areas in the county.

The graphical interface allows users to define both source area and drainage system stormwater control practices using a drag-and-drop interface, and the program and web site provides extensive program help and stormwater quality references.

P8

P8 - Program for Predicting Polluting Particle Passage through Pits, Puddles & Ponds, is a physically-based stormwater quality model developed by William Walker to predict the generation and transport of stormwater runoff pollutants in urban watersheds. The model simulates runoff and pollutant transport for a maximum of 24 watersheds, 24 stormwater best management practices (BMPs), 5 particle size classes, and 10 water quality components. The model simulates pollutant transport and removal in a variety of BMPs including swales, buffer strips, detention ponds (dry, wet and extended), flow splitters, and infiltration basins (offline and online). Model simulations are driven by a continuous hourly rainfall time series. P8 has been designed to require a minimum of site-specific data, which are expressed in terminology familiar to most engineers and planners. An extensive user interface providing interactive operation, spreadsheet-like menus, help screens and high resolution graphics facilitate model use.


BASINS

The Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) model is a multipurpose surface water environmental analysis system developed by the U.S. Environmental Protection Agency’s (EPA’s) Office of Water. The model was originally introduced in 1996 and has had subsequent releases in 1998 and 2001. BASINS allows for the assessment of large amounts of point and non-point source data in a format that is easy to use and understand. BASINS incorporates a number of model interfaces that it uses to assess water quality at selected stream sites or throughout the watershed. These model interfaces include:
  • QUAL2E: A water quality and eutrophication model
  • WinHSPF: A watershed scale model for estimating in-stream concentrations resulting from loadings from point and non-point sources
  • SWAT: A physical based, watershed scale model that was developed to predict the impacts of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land uses and management conditions over long periods of time.
  • PLOAD: A pollutant loading model.
PONDNET


The PONDNET model (Walker, 1987) is an empirical model developed to evaluate flow and phosphorous routing in Pond Networks. The following input parameters are defined by the user in evaluating the water quality performance of a pond: watershed area (acres), runoff coefficient, pond surface area (acres), pond mean depth (feet), period length (years), period precipitation (inches) and phosphorous concentrations (ppb). The spreadsheet is designed so that the phosphorous removal of multiple ponds in series can be evaluated.

WiLMS

The Wisconsin Lake Modeling Suite (WiLMS) is a screening level land use management/lake water quality evaluation tool developed by the Wisconsin Department of Natural Resources. It is a spreadsheet of thirteen lake model equations used to predict the total phosphorus (TP) concentration in a lake. TP loads can be entered either as point sources or by entering export coefficients for land uses. WiLMS can be downloaded for free at the Wisconsin DNR Web page.

Bathtub

Bathtub is an empirical model of reservoir eutrophication developed by the U.S. Army Corps of Engineers. Single basins can be modeled, in addition to a network of basins that interact with one another. The model uses steady-state water and nutrient balance calculations in a spatially segmented hydraulic network, which accounts for advective and diffusive transport and nutrient sedimentation.

WASP

WASP, Water Quality Analysis Simulation Program, is a model developed by the U.S. EPA to evaluate the fate and transport of contaminants in surface waters such as lakes and ponds. The model evaluates advection, dispersion, mass loading, and boundary exchange in one, two, or three dimensions. A variety of pollutants can be modeled with this program including nutrients, dissolved oxygen, BOD, algae, organic chemicals, metals, pathogens, and temperature.

SUSTAIN

SUSTAIN (System for Urban Stormwater Treatment and Analysis Integration) was developed by the USEPA to assist stormwater professionals in developing and implementing plans for stormwater flow and pollutant controls on a watershed scale. SUSTAIN contains seven modules that integrate with ArcGIS. Hydrology, hydraulics, and pollutant loading are computed using EPASWMM, Version 5. Sediment transport is based on HSPF. Modules include:
  • Framework manager
  • BMP siting tool
  • Land simulation module
  • BMP simulation module
  • Conveyance simulation
  • BMP optimization
  • Post-processor
MIDS Calculator

The MIDS Calculator was developed by the MPCA as an Excel-based stormwater quality tool to predict the annual pollutant removal performance of low impact development (LID) BMPs. The calculator will compute the volume reduction associated with infiltration practices plus the TSS and TP reductions for both LID and traditional BMPs, including permeable pavements, green roofs, bioretention, bioretention with underdrain (biofiltration), infiltration basin, tree trench, tree trench with underdrain, swale side slope, swale channels, swales with underdrains, wet swale, cistern/reuse, sand filter, constructed wetland and constructed stormwater pond.

STEPL

The Spreadsheet Tool for Estimating Pollutant Load (STEPL) was developed by the USEPA to calculate nutrient and sediment loads from different rural land uses and BMPs on a watershed scale. STEPL provides a user-friendly interface to create a customized spreadsheet-based model in Microsoft (MS) Excel. It computes watershed surface runoff; nutrient loads, including nitrogen, phosphorus, and 5-day biological oxygen demand (BOD5); and sediment delivery. The annual sediment load (sheet and rill erosion only) is calculated based on the Universal Soil Loss Equation (USLE) and the sediment delivery ratio. The sediment and pollutant load reductions that result from the implementation of BMPs are computed using the known BMP efficiencies.

Virginia Model


USEPA National Stormwater Calculator

The National Stormwater Calculator is a tool developed by the USEPA for computing small site hydrology for any location within the U.S. (www.epa.gov/nrmrl/wswrd/wq/models/swc/). It estimates the amount of stormwater runoff generated from a site under different development and control scenarios over a long term period of historical rainfall. The analysis takes into account local soil conditions, slope, land cover and meteorology. Different types of low impact development (LID) practices (also known as green infrastructure) can be employed to help capture and retain rainfall on-site. Future climate change scenarios taken from internationally recognized climate change projections can also be considered. The calculator’s primary focus is informing site developers and property owners on how well they can meet a desired stormwater retention target.
Đã ngâm cứu cái này chưa mấy cái này chưa
https://communities.bentley.com/pro...d_hydrology__wiki/3407/platform-compatibility
https://www.chijournal.org/C407
 

hoangdung

Moderator
Thành viên BQT
2/4/13
219
24
thanhhatran nói:
Có vè hoangdung không hiểu ý mình nói ... bản chất thoát nước xưa nay gồm 3 yếu tố:
- Mưa: mưa như thế nào ...
- Tập trung nước bề mặt
- Chảy trong hệ thống

Tách bạch kiểu chuyên ngành thì có thủy văn và thủy lực, thủy văn cung cấp đầu vào cho thủy lực. Ý mình nói là nói cái tiêu chuẩn rất ấm ớ Việt gian ...
- Sơ bộ thì độ cương giới hạn (hoặc tương tự)
- Xuất hàng thì dùng mô hình thủy lực ... nếu hàng xuất ra mà không đạt thì quay lại bước sơ bộ (sửa sơ bộ)

Người nào đã sử dụng phần mềm MIKE URBAN, SWMM, HEC-HMS hoặc TUFLOW sẽ hiểu các phần mềm này là tập hợp rất nhiều mô hình ... tuy nhiên một mô hình tính toán thoát nước thì bao gồm 2 mô hình: mô hình thủy văn và mô hình thủy lực ... thủy văn cung cấp cho bạn số lượng nước (dòng chảy) và thủy lực như thế nào nó chảy trong hệ thống của bạn.

Thủy văn thì lại liên quan đến mưa, với phương pháp tương tự thì dùng IDF .... với SWMM thì dùng mưa theo thời gian

Nghĩa là tiêu chuẩn ấm ớ
OK tôi hiểu nhầm được bạn nhầm lẫn giữa Phương Pháp với Mô Hình

Để sắp xếp thời gian tôi viết kỹ lại cái này - Mưa, Thủy Văn và Thủy Lực
 

hoangdung

Moderator
Thành viên BQT
2/4/13
219
24
hoangdung nói:
Để hy vọng mọi người hiểu rõ thế nào là Mô Hình thế nào là Phương Pháp

Lỡ copy thì hầu copy luôn - phòng đứt cáp dạo này trục trặc

https://stormwater.pca.state.mn.us/i...ecting_a_model

Available stormwater models and selecting a model

Hydrologic, hydraulic, and water quality models all have different purposes and will provide different information. The tables shown at the bottom of this page summarize some of the commonly used modeling software and modeling functions and the main purpose for which they were developed (NOTE: the information in these tables can be downloaded as an Excel file). The tables show the relative levels of complexity of necessary input data, indicate whether the model can complete a continuous analysis or is event based, list whether the model is in the public domain, and for hydraulic models indicate whether unsteady flow calculations can be conducted. For water quality models, the tables indicate whether the model is a receiving waters model, a loading model, or a BMP analysis model. The following definitions apply to the model functions.
  • Rainfall-Runoff Calculation Tool: peak flow, runoff volume, and hydrograph functions, only. More complex modeling should utilize hydrologic modeling which incorporate rainfall-runoff functions.
  • Hydrologic: includes rainfall-runoff simulation plus reservoir/channel routing.
  • Hydraulic: water surface profiles, flow rates, and flow velocities through waterways, structures and pipes. Models that include Green Infrastructure typically also assess how the BMPs managage the water through inflow, infiltration, evapotranspiration, storage and discharge.
  • Combined Hydrologic & Hydraulic: rainfall-runoff results become input into hydraulic calculations.
  • Water Quality: pollutant loading to surface waters or pollutant removal in a BMP.
  • BMP Calculators: spreadsheets that predict BMP performance, only.
Defining Model Objectives and Selecting a Stormwater Model


Environmental modeling, including stormwater and water quality modeling, is complex given the purpose is to mathematically predict natural processes (USEPA, 2009). Models range from simple spreadsheets that predict a single process such as the runoff from a single storm, to complex simulations that predict multiple, inter-related processes including performance of multiple BMPs. A greater amount of uncertainty is inherent in the more complex models, which results in more complexity in model calibration (WEF, 2012). For example, estimating peak runoff rates is a different problem than estimating the peak elevation of a water body and could require the use of a different model. A model able to estimate phosphorus loading from a network of detention ponds may not be able to model the phosphorus loading from an infiltration pond.

Therefore it is important that modelers select a stormwater modeling tool that is based on both modeling objectives and available resources. The USEPA recommends that the first step in development of a model is to define the objectives (USEPA, 2009). When defining the modeling objectives, the modelers and decision-makers should consider the following (WEF, 2012):
  • Regulatory compliance: is the model required for regulatory compliance? Which models are accepted by the regulatory agency?
  • Hydrologic process: is the goal to model a single storm event or continuous rainfall? Should the model incorporate infiltration, evaporation, transpiration, abstraction, and other physical processes that reduce the volume of runoff? Is the model required to predict large storm events (for flood control), small storm events (for water quality predictions), or both?
  • Land use: is the model required for large rural/agricultural catchments or small urban catchments?
  • Area to be modeled: will the model be required to predict stormwater for individual blocks? Or is a larger catchment scale acceptable?
  • Intended use: is the intended use for planning purposes, engineering/design, or operational performance?
  • Model complexity: will a simple model be sufficient?
  • Modeler experience: what is the model-specific expertise of current staff? Is there budget to hire an expert?
The actual process of selecting a model is likely to be an iterative process of model evaluation, adjustments to objectives and/or costs, re-evaluation, and ultimately model selection. Potentially, modelers may select multiple models to meet the objectives of the study. For example one model may be best for hydrology and hydraulics, while another may be best for BMP performance. In these circumstances the modelers should investigate the ability of the models to be linked (USEPA, 2009).



Summary of Common Stormwater Models


The following section describes the most common stormwater models used by stormwater professionals. Use the hyperlinks for additional information on these models.

Rational method

The Rational Method is a simple hydrologic calculation of peak flow based on drainage area, rainfall intensity, and a non-dimensional runoff coefficient. The peak flow is calculated as the rainfall intensity in inches per hour multiplied by the runoff coefficient and the drainage area in acres. The peak flow, Q, is calculated in cubic feet per second (cfs) as Q = CiA where C is the runoff coefficient, i is the rainfall intensity, and A is the drainage area. A conversion factor of 1.008 is necessary to convert acre-inches per hour to cfs, but this is typically not used. This method is best used only for simple approximations of peak flow from small watersheds.

HEC-HMS

HEC-HMS is a hydrologic rainfall-runoff model developed by the U.S. Army Corps of Engineers that is based on the rainfall-runoff prediction originally developed and released as HEC-1. HEC-HMS is used to compute runoff hydrographs for a network of watersheds. The model evaluates infiltration losses, transforms precipitation into runoff hydrographs, and routes hydrographs through open channel routing. A variety of calculation methods can be selected including SCS curve number or Green and Ampt infiltration; Clark, Snyder or SCS unit hydrograph methods; and Muskingum, Puls, or lag routing methods. Precipitation inputs can be evaluated using a number of historical or synthetic methods and one evapotranspiration method. HEC-HMS is used in combination with HEC-RAS for calculation of both the hydrology and hydraulics of a stormwater system or network.

TR-20

Natural Resources Conservation Service Technical Release No. 20 (TR-20): Computer Program for Project Formulation Hydrology was developed by the hydrology branch of the U.S.D.A. Soil Conservation Service in 1964. It was recently updated to allow users to import Atlas 14 precipitation data available from NOAA.

WinTR-20 is a single event watershed scale runoff and routing (hydrologic) model that is best suited to predict stream flows in large watersheds. It computes direct runoff and develops hydrographs resulting from any synthetic or natural rainstorm. Developed hydrographs are routed through stream and valley reaches as well as through reservoirs. Hydrographs are combined from tributaries with those on the main stream. Branching flow (diversion), and baseflow can also be accommodated. WinTR-20 may be used to evaluate flooding problems, alternatives for flood control (reservoirs, channel modification, and diversion), and impacts of changing land use on the hydrologic response of watersheds. A new routine has been added to the program that allows the user to import NOAA Atlas 14 rainfall data for site-specific applications. The rainfall-frequency data will be used to develop site-specific rainfall distributions. The NOAA 14 text files for selected states are available in the Support Materials for downloading and use in WinTR-20 Version 1.11. The NOAA 14 text files and supporting GIS files are packaged in a zip file for each state.

Win TR-55

Technical Release 55 (TR-55; Urban Hydrology for Small Watersheds) was developed by the U.S.D.A. Soil Conservation Service, now the Natural Resources Conservation Service (NRCS), in 1975 as a simplified procedure to calculate storm runoff volume, peak rate of discharge, hydrographs and storage volumes in small urban watersheds. In 1998, Technical Release 55 and the computer software were revised to what is now called WinTR-55. The changes in this revised version of TR-55 include: upgraded source code to Visual Basic, changed philosophy of data input, development of a Windows interface and output post-processor, enhanced hydrograph-generation capability of the software and flood routing hydrographs through stream reaches and reservoirs. WinTR-55 is a single-event rainfall-runoff small watershed hydrologic model. The model is an input/output interface which runs WinTR-20 in the background to generate, route and add hydrographs. The WinTR-55 generates hydrographs from both urban and agricultural areas at selected points along the stream system. Hydrographs are routed downstream through channels and/or reservoirs. Multiple sub-areas can be modeled within the watershed. A rainfall-runoff analysis can be performed on up to ten sub-areas and up to ten reaches. The total drainage area modeled cannot exceed 25 square miles.

HEC-RAS

HEC-RAS is a river hydraulics model developed by the U.S. Army Corps of Engineers to compute one-dimensional water surface profiles for steady or unsteady flow. HEC-RAS is an updated version of HEC-2. Computation of steady flow water surface profiles is intended for flood plain studies and floodway encroachment evaluations. HEC-RAS uses the solution of the one-dimensional energy equation with energy losses evaluated for friction and contraction and expansion losses in order to compute water surface profiles. In areas with rapidly varied water surface profiles, HEC-RAS uses the solution of the momentum equation. Unsteady flow simulation can evaluate subcritical flow regimes as well as mixed flow regimes including supercritical, hydraulic jumps, and draw downs. Sediment transport calculation capability will be added in future versions of the model. The HEC-RAS program is available to the public from the U.S. Army Corps of Engineers. HEC-RAS utilizes the hydrologic results that are developed in HEC-HMS.

WSPRO

WSPRO is a hydraulic model for water surface profile computations developed by the U.S. Geological Survey. The model evaluates one-dimensional water surface profiles for systems with gradually varied, steady flow. The open channel calculations are conducted using backwater techniques and energy balancing methods. Single opening bridges use the orifice flow equation and flow through culverts is computed using a regression equation at the inlet and an energy balance at the outlet. The WSPRO program is available to the public and can be downloaded from the U.S. Geological Survey.


CULVERTMASTER

CulvertMaster is a hydraulic analysis program for culvert design. The model uses the U.S. Federal Highway Administration Hydraulic Design of Highway Culverts methodology to provide estimates for headwater elevation, hydraulic grade lines, discharge, and culvert sizing. Rainfall and watershed analysis using the SCS Method or Rational Method can be incorporated if the peak flow rate is not known. CulvertMaster is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.


FLOWMASTER

FlowMaster is a hydraulic analysis program used for the design and analysis of open channels, pressure pipes, inlets, gutters, weirs, and orifices. Mannings, Hasen-Williams, Kutter, Darcy- Weisbach, or Colebrook-White equations are used in the calculations. FlowMaster is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.

HydroCAD

HydroCAD is a computer aided design program for modeling the hydrology and hydraulics of stormwater runoff. Runoff hydrographs are computed using the SCS runoff equation and the SCS dimensionless unit hydrograph. For the hydrologic computations, there is no provision for recovery of initial abstraction or infiltration during periods of no rainfall within an event. The program computes runoff hydrographs, routes flows through channel reaches and reservoirs, and combines hydrographs at confluences of the watershed stream system. HydroCAD has the ability to simulate backwater conditions by allowing the user to define the backwater elevation prior to simulating a rainfall event. HydroCAD is a proprietary model and can be obtained from HydroCAD Software Solutions LLC.

PondPack

PondPack is a program for modeling and design of the hydrology and hydraulics of storm water runoff and pond networks. Rainfall analyses can be conducted using a number of synthetic or historic storm events using methods such as SCS rainfall distributions, intensity-duration-frequency curves, or recorded rainfall data. Infiltration and runoff can be computed using the SCS curve number method or the Green and Ampt or Horton infiltration methods. Hydrographs are computed using the SCS Method or the Rational Method. Channel routing is conducted using the Muskingun, translation, or Modified Puls methods. Outlet calculations can be performed for outlets such as weirs, culverts, orifices, and risers. The program can assist in the determination of pond sizes. PondPack is a proprietary model that can be obtained from Haestad Methods, Bentley Systems, Inc.


SWMM-Based programs (SWMM5, PC-SWMM, InfoSWMM, MikeUrban)

SWMM-Based Programs SWMM is a hydraulic and hydrologic modeling system that also has a water quality component. Please see the full description above for more details on the model. The Storm Water Management Model (SWMM) was originally developed for the Environmental Protection Agency (EPA) in 1971. SWMM is a dynamic rainfall-runoff and water quality simulation model, primarily but not exclusively for urban areas, for single-event or long-term (continuous) simulation. Version 5 of SWMM was developed in 2005 and has been updated multiple times since. The Storm Water Management Model (SWMM) is a comprehensive computer model for analysis of quantity and quality problems associated with urban runoff. Both single-event and continuous simulation can be performed on catchments having storm sewers, or combined sewers and natural drainage, for prediction of flows, stages and pollutant concentrations. Extran Block solves complete dynamic flow routing equations (St. Venant equations) for accurate simulation of backwater, looped connections, surcharging, and pressure flow. A modeler can simulate all aspects of the urban hydrologic and quality cycles, including rainfall, snow melt, surface and subsurface runoff, flow routing through drainage network, storage and treatment. Statistical analyses can be performed on long-term precipitation data and on output from continuous simulation. SWMM can be used for planning and design. Planning mode is used for an overall assessment of urban runoff problem or proposed abatement options. Current update of SWMM includes the capability to model the flow rate, flow depth and quality of Low Impact Development (LID) controls, including permeable pavement, rain gardens, green roofs, street planters, rain barrels, infiltration trenches, and vegetative swales The SWMM program is available to the public. The proprietary shells, PC-SWMM, InfoSWMM, and Mike Urban, provide the basic computations of EPASWMM with a graphic user interface, additional tools, and some additional computational capabilities.

XPSWMM

XPSWMM is a propriety model that originally began as a SWMM based program. The model developer has developed many upgrades that are independent of the USEPA upgrades to SWMM. Because of these upgrades the two software platforms are no longer interchangeable. XP SWMM does have a function that allows model data to be exported in SWMM format. Comparison of model results between the two softwares will result in similar, but not identical, results.

XP SWMM’s hydrologic and hydraulic capabilities includes modeling of floodplains, river systems, stormwater systems, BMPs (including green infrastructure), watersheds, sanitary sewers, and combined sewers. Pollutant modeling capabilities include pollutant and sediment loading and transport as well as pollutant removal for a suite of BMPs. XP-SWMM is available from XP Solutions.


WinSLAMM

The Source Loading and Management Model is a stormwater quality model developed for the USGS by John Voorhees and Robert Pitt for evaluation of nonpoint pollution in urban areas. The model is based on field observations of grass swales, wet detention ponds, porous pavement, filter strips, cisterns and rain barrels, hydrodynamic settling devices, rain gardens/biofilters and street sweeping, as either other source area or outfall control practices. The focus of the model is on small storm hydrology and particulate washoff. The WinSLAMM model may be obtained from PV & Associates. Wisconsin data files for input into SLAMM may be obtained from the U.S. Geological Survey, and the model provides an extensive set of rainfall, runoff and particulate solids and other pollutant files developed from the National Stormwater Quality Data Base for most urban areas in the county.

The graphical interface allows users to define both source area and drainage system stormwater control practices using a drag-and-drop interface, and the program and web site provides extensive program help and stormwater quality references.

P8

P8 - Program for Predicting Polluting Particle Passage through Pits, Puddles & Ponds, is a physically-based stormwater quality model developed by William Walker to predict the generation and transport of stormwater runoff pollutants in urban watersheds. The model simulates runoff and pollutant transport for a maximum of 24 watersheds, 24 stormwater best management practices (BMPs), 5 particle size classes, and 10 water quality components. The model simulates pollutant transport and removal in a variety of BMPs including swales, buffer strips, detention ponds (dry, wet and extended), flow splitters, and infiltration basins (offline and online). Model simulations are driven by a continuous hourly rainfall time series. P8 has been designed to require a minimum of site-specific data, which are expressed in terminology familiar to most engineers and planners. An extensive user interface providing interactive operation, spreadsheet-like menus, help screens and high resolution graphics facilitate model use.


BASINS

The Better Assessment Science Integrating Point and Nonpoint Sources (BASINS) model is a multipurpose surface water environmental analysis system developed by the U.S. Environmental Protection Agency’s (EPA’s) Office of Water. The model was originally introduced in 1996 and has had subsequent releases in 1998 and 2001. BASINS allows for the assessment of large amounts of point and non-point source data in a format that is easy to use and understand. BASINS incorporates a number of model interfaces that it uses to assess water quality at selected stream sites or throughout the watershed. These model interfaces include:
  • QUAL2E: A water quality and eutrophication model
  • WinHSPF: A watershed scale model for estimating in-stream concentrations resulting from loadings from point and non-point sources
  • SWAT: A physical based, watershed scale model that was developed to predict the impacts of land management practices on water, sediment and agricultural chemical yields in large complex watersheds with varying soils, land uses and management conditions over long periods of time.
  • PLOAD: A pollutant loading model.
PONDNET


The PONDNET model (Walker, 1987) is an empirical model developed to evaluate flow and phosphorous routing in Pond Networks. The following input parameters are defined by the user in evaluating the water quality performance of a pond: watershed area (acres), runoff coefficient, pond surface area (acres), pond mean depth (feet), period length (years), period precipitation (inches) and phosphorous concentrations (ppb). The spreadsheet is designed so that the phosphorous removal of multiple ponds in series can be evaluated.

WiLMS

The Wisconsin Lake Modeling Suite (WiLMS) is a screening level land use management/lake water quality evaluation tool developed by the Wisconsin Department of Natural Resources. It is a spreadsheet of thirteen lake model equations used to predict the total phosphorus (TP) concentration in a lake. TP loads can be entered either as point sources or by entering export coefficients for land uses. WiLMS can be downloaded for free at the Wisconsin DNR Web page.

Bathtub

Bathtub is an empirical model of reservoir eutrophication developed by the U.S. Army Corps of Engineers. Single basins can be modeled, in addition to a network of basins that interact with one another. The model uses steady-state water and nutrient balance calculations in a spatially segmented hydraulic network, which accounts for advective and diffusive transport and nutrient sedimentation.

WASP

WASP, Water Quality Analysis Simulation Program, is a model developed by the U.S. EPA to evaluate the fate and transport of contaminants in surface waters such as lakes and ponds. The model evaluates advection, dispersion, mass loading, and boundary exchange in one, two, or three dimensions. A variety of pollutants can be modeled with this program including nutrients, dissolved oxygen, BOD, algae, organic chemicals, metals, pathogens, and temperature.

SUSTAIN

SUSTAIN (System for Urban Stormwater Treatment and Analysis Integration) was developed by the USEPA to assist stormwater professionals in developing and implementing plans for stormwater flow and pollutant controls on a watershed scale. SUSTAIN contains seven modules that integrate with ArcGIS. Hydrology, hydraulics, and pollutant loading are computed using EPASWMM, Version 5. Sediment transport is based on HSPF. Modules include:
  • Framework manager
  • BMP siting tool
  • Land simulation module
  • BMP simulation module
  • Conveyance simulation
  • BMP optimization
  • Post-processor
MIDS Calculator

The MIDS Calculator was developed by the MPCA as an Excel-based stormwater quality tool to predict the annual pollutant removal performance of low impact development (LID) BMPs. The calculator will compute the volume reduction associated with infiltration practices plus the TSS and TP reductions for both LID and traditional BMPs, including permeable pavements, green roofs, bioretention, bioretention with underdrain (biofiltration), infiltration basin, tree trench, tree trench with underdrain, swale side slope, swale channels, swales with underdrains, wet swale, cistern/reuse, sand filter, constructed wetland and constructed stormwater pond.

STEPL

The Spreadsheet Tool for Estimating Pollutant Load (STEPL) was developed by the USEPA to calculate nutrient and sediment loads from different rural land uses and BMPs on a watershed scale. STEPL provides a user-friendly interface to create a customized spreadsheet-based model in Microsoft (MS) Excel. It computes watershed surface runoff; nutrient loads, including nitrogen, phosphorus, and 5-day biological oxygen demand (BOD5); and sediment delivery. The annual sediment load (sheet and rill erosion only) is calculated based on the Universal Soil Loss Equation (USLE) and the sediment delivery ratio. The sediment and pollutant load reductions that result from the implementation of BMPs are computed using the known BMP efficiencies.

Virginia Model


USEPA National Stormwater Calculator

The National Stormwater Calculator is a tool developed by the USEPA for computing small site hydrology for any location within the U.S. (www.epa.gov/nrmrl/wswrd/wq/models/swc/). It estimates the amount of stormwater runoff generated from a site under different development and control scenarios over a long term period of historical rainfall. The analysis takes into account local soil conditions, slope, land cover and meteorology. Different types of low impact development (LID) practices (also known as green infrastructure) can be employed to help capture and retain rainfall on-site. Future climate change scenarios taken from internationally recognized climate change projections can also be considered. The calculator’s primary focus is informing site developers and property owners on how well they can meet a desired stormwater retention target.
Viết mấy cái này bằng tiếng Việt mất thời gian quá, trong khi đó thì link tiếng Anh đầy nhóc, ai không biết tiếng Anh đọc nội dung bằng tiếng Việt cũng như Vịt nghe sấm
 

haiha11

Thành viên cơ bản
18/6/19
1
2
Hi anh chị ơi,
Em đang học về phần mềm Xp-SWMM mô phỏng lũ lụt của đô thị, tuy nhiên tài liệu về phần mềm này rất ít. Chỉ có trên Tutorial của web chính.
anh chị nào có kinh nghiệm mô phỏng 2D phần mềm này có thể cho em hỏi , em muốn xác định ngưỡng ngập lụt thì mô hình 2D cần những data gì và có tài liệu cho em xin được không ạ?
 

thanhhatran

Thành viên chính thức
7/3/14
40
8
Hi anh chị ơi,
Em đang học về phần mềm Xp-SWMM mô phỏng lũ lụt của đô thị, tuy nhiên tài liệu về phần mềm này rất ít. Chỉ có trên Tutorial của web chính.
anh chị nào có kinh nghiệm mô phỏng 2D phần mềm này có thể cho em hỏi , em muốn xác định ngưỡng ngập lụt thì mô hình 2D cần những data gì và có tài liệu cho em xin được không ạ?
XP-SWMM cơ bản là dùng lõi SWMM5 của EPA, khi bạn dùng thành thão SWMM5 thì dĩ nhiên sử dụng XP-SWMM không khó. Nôm na là tập bò trước. Hướng dẫn sử dụng SWMM5 bằng tiếng Việt thì bạn vui lòng Google.

Với môi trường Việt Nam - mình khuyên bạn nên sử dụng SSA - Storm and sanitary analysis của Autodesk vì sử dụng được nền data AutoCAD
lý do đơn giản là có thuốc và tương tác được với các phần mềm thiết kế hạ tầng khác
hướng dẫn sử dụng SSA 2013 bằng tiếng Việt cũng đầy nhóc trên mạng

Nếu muốn Pro thì nhảy qua nghiên cứu các sản phẩm của Bentley - nhưng cái này hiếm thuốc - mua bản quyền thì giá trên trời.
Nhưng ưu điểm của Bentley là mô phỏng ngập lụt 3D giống như XP-SWMM hay PC-SWMM

Còn XP-SWMM rồi PC-SWMM thì bó hẹp là không sử dụng được bản đồ nền từ AutoCad (gia công lại rất vất vả) mà sử dụng nền ArcGIS (ESRI shape files ) hoặc MapInfo (MapInfo mif files), mà ba thứ này thì chủ yếu xin bên địa chính nhưng gần như dữ liệu độ cao rất hiếm
muốn xác định ngưỡng ngập lụt thì mô hình 2D - thì như đã nói trên bạn tìm đọc các tài liệu hướng dẫn SWMM5 hoặc SSA rồi đưa từng tình huống cụ thể, đem lên đây mình giải đáp cho, còn hỏi chung chung như bạn thì khoảng 20 trang A4.
 

TuLeKG

Thành viên chính thức
Nhân tiện có đề tài này, mình có vài lượm lặt

1. Các thông số khí tượng của quan hệ IDF được giới thiệu trong tiêu chuẩn thiết kế mạng lưới thoát nước hiện hành (TCVN 7957-2008) được xác định từ tài liệu mưa trong quá khứ cách đây khá lâu nên cần được cập nhật, điều chỉnh hoặc xây dựng mới với tài liệu mưa gần đây. Cần phải xây dựng lại theo hướng dẫn tài liệu sau

2. Về Rational Method đã nêu trong TCVN 7957:2008 , thì bản thân ở diễn đàn này cũng đề cập đây là phương án nông dân thời mông muội, có trích dẫn cho mọi người theo link này

lưu ý là giới hạn 80ha, vùng cao, không có hồ chứa
 

TuLeKG

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Nhân tiện đây cũng muốn hỏi mọi người cái Độ Cương Giới Hạn trong TCVN 7957-2008 có phải là Peak Discharge Method
không hiểu gốc của cái này cảm thấy khó chịu quá, tìm mãi không ra tài liệu tiếng Anh nào nói về Độ Cương Giới Hạn cả
 

TongVanVu

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20/5/19
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Một đề tài khá hay trong việc tính toán tiêu thoát nước cho đô thị, khi quá trình đô thị hóa đang diễn ra khá mạnh mẽ, chi tiêu cho các công trình thoát nước đô thị và các cơ sở kiểm soát ô nhiễm là một trong những khoản mục lớn nhất trong ngân sách của hầu hết các thành phố. Việc tính toán không thể dùng bảng tính Excel dựa trên Phương pháp cường độ mưa giới hạn mà cần phải sử dụng các phần mềm máy tính. Vấn đề hiện nay phải xác định được chính xác mô hình dòng chảy đô thị (urban runoff models) phù hợp với thực tế.

Việc sử dụng mô hình thủy lực để mô phỏng dòng chảy đô thị (hydrologic models for urban flow simulation followed) đầu tiên là RRL Model (Road Research Laboratory) của Phòng thí nghiệm nghiên cứu đường bộ Mỹ, tiếp theo là Chicago Model (Watkins, 1962, Kiefer, 1970). Sau đó ở Mỹ tiếp tục sản sinh nhiều mô hình nữa như EPA’s SWMM, WRE model, Chicago Model in the U.S. (Watkins, 1962, Kiefer, 1970), University of Cincinnati model, ILLUDAS, MIT, HYDROCOMP ...

Trong 30 năm qua, có rất nhiều mô hình máy tính ( computer models) được sử dụng cho nhiều lĩnh vực khác nhau trong việc tính toán tiêu thoát nước, mô hình thủy lực (sử dụng máy tính) trở thành một phần không thể thiếu trong thiết kế và phân tích thủy văn và thủy lực, các mô hình đã du nhập vào Việt Nam bao gồm:

1. Của Công Binh Lục Quân Mỹ (United States Army Corps of Engineers - USACE - ở Mỹ việc quản lý hồ đập, kênh rạch và chống lũ giao cho Quân đội), gọi là nhóm USACE Hydrologic Engineering Cente như sau:
- HEC-1 (Flood hydrograph package)(U.S.A.C.E., 1973)
- HEC-2 (Water surface profiles)(U.S.A.C.E., 1976)
- STORM (Storage, Treatment, and Overflow Runoff) Model (U.S.A.C.E., 1977)

2. U.S. Soil Conservation Service (để tiếng Anh để mọi người dễ Google)
- TR-20 ( Project formulation hydrology)(U.S.S.C.S, 1965)
- WSP2 (Water surface profile computations)(U.S.S.C.S., 1976)

3. U.S. Environmental Protection Agency , đấy chính là cái mô hình SWMM (Stormwater Management) Model (Metcalf and Eddy, 1971) đầy tranh cãi hiện nay dù nó ra đời lâu rồi, du nhập vào Việt Nam bắt nguồn từ dự án Nhiêu Lộc Thị Nghè được thực hiện bởi tư vấn Camp Dresser&McKee International Inc (Mỹ).

4. Ngoài ra còn có nhiều mô hình khác nhau như @hoangdung đã đề cập ở #4, bên thủy lợi thì nổi trội nhất là dòng họ nhà Mike (MIKE Powered by DHI), với thoát nước đô thị là mô hình máy tính Mike Urban gói gọn nhiều mô hình thủy lực thoát nước đô thị khác nhau. Nhưng Mike có thể gọi là mô hình đóng - mô hình độc quyền, không chia sẻ. Mike Urban hoạt động dự trên 2 lõi tính toán lập mô hình là MOUSE-HD và SWMM5, gồm có các Module con:
+ CS – PipeFlow: Mô phỏng dòng chảy không ổn định trong ống và kênh dẫn.
+ CS – Control: được xem là có khả năng vận hành giám sát theo thời gian thực các đập tràn, cửa xả, máy bơm… Nó cho phép mô tả hoạt động của các thiết bị điều khiển và đưa ra lô gic rõ ràng về cách thức vận hành của thiết bị điều khiển.
+ CS – Rainfall-Runoff: Mô phỏng lượng mưa – dòng chảy theo thời gian trong khu vực, theo sóng động lực, hồ chứa tuyến tính…
+ CS – Pollution Transport: Mô phỏng sự lan truyền và khuếch tán các chất ô nhiễm trong đó có cả bùn cát. Bao gồm cả lập mô hình chất lượng nước khi lập mô hình lan truyền các chất ô nhiễm từ nước mặt xuống hệ thống thải.

Tuy nhiên do sự độc quyền, nhiều mô hình không đến được tay người dùng Việt, may mà có các tổ chức như U.S. Environmental Protection Agency (USEPA), U.S. Geological Survey (USGS), U.S. Hydrologic Engineering Center (HEC) of Army Corps of Engineers, Federal Highway Administration (FHA) of U.S. Department of Transportation, and Natural Resources Conservation Service (NRCS) of U.S. Department of Agriculture mà các người Việt có cơ hội tiếp cận:
1. BASINS (GIS ARCVIEW-based point and nonpoint sources modeling and analysis based on watershed management approach, USEPA)
2. FEQ (solving St. Venant equations in open channels and through control structures, USGS)
3. HEC-1 (rainfall-runoff modeling, HEC)
4. HEC-GeoRAS (GIS ARC/ INFO and ARCVIEW-based tool for use with HEC-RAS for cross-section cutting and automatic floodplain delineation, HEC)
5. HEC-RAS (one-dimensional hydraulic calculations by solving energy and momentum equations, HEC)
6. HEC-HMS (rainfall-runoff modeling with graphical user interface, HEC)
7. HSPEXP (an Expert System for calibration of HSPF model, USGS)
8. HSPF (rainfall-runoff modeling and water quality modeling, USEPA and USGS)
9. HYDRAIN (a package of seven computer models for storm drain and sanitary sewer design, open channel water surface analysis, culvert design and analysis, channel lining design, USGS regression equations, FHA)
10. SWMM (urban runoff quantity and quality modeling, USEPA)
11. TR-20 (rainfall-runoff modeling, NRCS)
12. TR-55 (rainfall-runoff modeling for small watersheds, NRCS)
13. UNET (one-dimensional unsteady flow modeling, HEC)
(để nguyên tiếng Anh để mọi người dễ Google tìm hiểu)

Với 13 mô hình liệt kê ở trên, đánh giá cao hiện nay vẫn là HEC-1 and HEC-2 cùng với các phiên bản tương ứng là HEC-HMS và HEC-RAS, tiếp theo vẫn là SWMM. Với TR-20 có thể xem xét tương đương với HEC-1.

Tùy theo quy mô dự án mà chọn mô hình thủy lực thích hợp và phương pháp phân tích hệ thống để cho phép tái tạo và mô phỏng được những quá trình mưa úng trên lưu vực, đánh giá được mức độ ảnh hưởng khác nhau của các công trình đối với quá trình tiêu nước trên toàn lưu vực, giúp lựa chọn được những phương án quy hoạch, thiết kế và quản lý tối ưu các hệ thống tiêu thoát nước.

Không đồng ý với bài viết của bạn @tainguyenviet tại bài viết Ngập lụt đô thị - có đóng góp không nhỏ bởi sự lạc hậu và phi lý của TCVN 7957:2008, tiêu chuẩn đã rất mở rộng cho việc áp dụng mô hình thủy lực, tuy nhiên yêu cầu bất di bất dịch phải lập bảng tính tường minh bằng bằng phương pháp cường độ giới hạn hoặc phương pháp Rational, còn sau đó thì bắt buộc phải áp dụng mô hình thủy lực.

Tại sao vậy, dù ngày nay công nghệ khoa học đã phát triển, tính toán thoát nước bằng máy tính từ 1D đã chuyển sang 2D với sự hỗ trợ của GIS (Geographical Information System), tuy nhiên đánh giá tường minh bằng các con tính cụ thể vẫn rất cần thiết, đừng bao giờ cho rằng kết quả của máy tính luôn luôn đúng. Ngay cả cùng một mô hình thủy lực, cũng cần phải sử dụng nhiều phần mềm để so sánh. Rồi cùng trong một phần mềm đó, có thể áp dụng các mô hình khác để kiểm toán lại.
 

dotu2011xd

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1/9/19
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Cảm ơn sư huynh @TongVanVu đã lược khảo, nhớ một thời cánh bên thủy lợi cứ đem Mike ra dọa nhau , mãi nhờ các tổ chức công ở Hoa Kỳ miễn phí các phần mềm thì mới có cơ hội tiếp cận thủy lực điện toán (nói như một VK thôi :D).

Nhân tiện bàn về phần mềm, mong sư huynh và ACE khác cho nhận xét xem ưu nhược điểm của 2 tên SSA (Autodesk® Storm and Sanitary Analysis) và Bentley SewerGEMS ? nhận thấy SSA dễ chịu hơn , dễ sử dụng hơn, và bao gọn các tính năng khác của các phần mềm khác:
- Bentley’s StormCAD, Pondpack, CivilStorm, SewerCAD, SewerGEMS, CulvertMaster
- XP SWMM
- PC SWMM
- HydroCAD
- MWHsoft/Wallingford InfoWorks
SSA dễ chịu vì:
- Dễ sử dụng với giao diện đồ họa rất tường minh
- Mô hình mưa và mô hình thủy lực có thể linh hoạt tùy biến
- Truy cập dữ liệu dễ dàng từ Civil 3D và Map 3D
- SSA có thể tạo các tệp GIS SHP, bảng tính Excel, báo cáo, video hoạt hình và đồ họa ...

Theo giới thiệu của thầy Sáu Phạm Ngọc GV KTĐT trường ĐH Kiến Trúc TP.HCM thì SewerGEMS có một số ưu điểm nổi bật như sau
1. Thiết kế được đường kính cống thoát nước tự động (ít có phần mềm nào làm được điều này) cho cả nước mưa và nước thải.
2. Phân tích CSO - giếng tách dòng trong hệ thống thoát nước nửa riêng.
3. Mô phỏng vận hành bơm
4. Thiết kế hồ điều tiết
5. Tính toán thiết kế nước mưa chi tiết đến từng giếng thu.
6. Tạo các phương án so sánh ngay trên một file.
Ưu điểm là dự án càng lớn, áp dụng SewerGEMS càng hay.

Nhưng sử dụng thử thì thấy SewerGEMS có giao diện đồ họa tệ hơn SSA, được cái là Bentley có vẻ hỗ trợ support tốt hơn Autodesk
 
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So sánh giữa SSA với SewerGEMS thì nhận thấy giống như so sánh giữa xe Toyota với xe Mercedes, nếu chỉ tính toán đơn giản thì cứ SSA mà tẩn với khả năng chịu lỗi cao hơn nhiều so với SewerGEMS, tuy nhiên nếu có dữ liệu địa hình lưu vực đầy đủ thì tại sao không SewerGEMS, với Using Downstream Trace and Digital Terrain Models
Contours-and-Boundary2.PNG


thì hy vọng tương lại gần SewerGEMS đè bẹp PC SWMM.

Một đặc tính ưu việt mà SSA không có được là tính năng Global Storm Events, đấy là có thể nhét đường cong mưa IDF để chạy cho mô hình SWMM, đặc biệt là có thể sử dụng SewerGEMS (sử dụng phương pháp khối xen kẽ) để xây dựng mô hình mưa tích lũy (time-depth) cho SWMM từ IDF nếu có số liệu các trận mưa, trò chơi này trước đây toàn phải lạy lục các bạn bên khi tượng thủy văn )đương nhiên thì thời buổi cạnh trạnh sợ mất khách hàng PC SWMM cũng đã nhét thêm tính năng này cũng như cho phép tương tích với Civil 3D).

đặc biệt là khá yêu thích cái này Switch between standard SWMM solver and Bentley enhanced
solver-compatibility.jpg


với cái món On Grade/HEC-22 Inlet Calculations, Node Headlosses, Pond Outlet Structures ưu việt hơn hẳn nếu chỉ sử dụng đơn thuần SWMM

Với giao diện Ribbon, thì có thể nói là SewerGEMS ngày càng dễ sử dụng như SSA ... hiện tại thì đang ngâm cứu cái món Terrain Model có trong
SewerGEMS Update 2) , đặc biệt là cái món Surface (Gutter) System có gì hay sẽ bá cáo với mọi người

Về hỗ trợ và hướng dẫn sử dụng thì Bentley có vẻ ăn đứt Autodsek, toàn cứ vào đây xem xét

Sơ bộ nhận thấy nếu sử dụng Autodesk Civil 3D LandXML , sau khi xuất ra được file LandXML thì việc gì phải kiêng cữ SewerGEMS nữa, vì có cái ưu điểm là khỏi lập bảng Excel khi sử dụng phương pháp thích hợp (Rational) cho các lưu vực nhỏ.
 
Dù đã viết ở bên này "Ngập lụt đô thị - có đóng góp không nhỏ bởi sự lạc hậu và phi lý của TCVN 7957:2008" , nhưng mình cũng bổ sung tiếp cho bên này ... vì nhiều người không rõ cái thuật ngữ Mô Hình Thủy Lực nêu trong TCVN 7957:2008, phải hiểu rõ đây là Mô Hình Máy Tính/ Mô Hình Điện Toán thì đúng hơn, nói trắng trợn ra là phần mềm thủy lực. Mục đích của việc sử dụng phần mềm để tính toán mưa – dòng chảy và diễn toán thủy lực trong hệ thống thoát nước nhằm kiểm tra lại kết quả sơ bộ ở bước thứ nhất.

Phần mềm thủy lực nào thì cũng có 2 phần chính là tính toán lưu lượng mưa dòng chảy đến điểm thu, và kiểm toán vận chuyển nước mưa ra khỏi hệ thống:
- Về tính toán lưu lượng mưa thì các phần mềm miễn phí như HEC-RAS hay EPA SWMM thì chỉ một vài phương pháp/cách thức hay mô hình tập trung dòng chảy mưa trên bề mặt (Runoff), các phần mềm thương mại như SewerGEM và SSA ... thì có nhiều cách thức (phương pháp) hay mô hình tập trung dòng chảy bề mặt.
- Về vận chuyển nước mưa (Flow Routing) thì loanh quanh có 3 phương pháp: dòng chảy đều, dòng chảy sóng động lực (theo cao đô bề mặt của dòng chảy) và dòng chảy thủy động lực (tổng hợp tất cả các yếu tố của dòng chảy).

Ở Việt Nam hiện nay thì tính toán lưu lượng mưa hiện đang phổ biến 3 cách: độ cương giới hạn D. F. Gorbachev (1920) , Rational Method và SWMM (Stormwater Management Model), còn vận chuyển nước mưa thì như đã nói trên: dòng chảy đều, dòng chảy sóng động lực và dòng chảy thủy động lực.

Tiếu lâm nhất là giờ đến nay vẫn chưa Google được cái độ cương giới hạn D. F. Gorbachev (1920), nếu theo TCVN 7957:2008 và khả năng tiếng Anh bập bõm thì nghi ngờ nó giống cái UK Modified Rational thì phải, copy nguyên cụm từ hướng dẫn sử dụng phần mềm InfoDrainage phần mềm XPDRAINAGE

Peak Flow Calculation
Select the calculation method to be used when sizing the pipes/channels. Choose from:
* Rational Method: Flow = Rainfall Intensity x Total Area + Total Base Flow
* (UK) Modified Rational Method: Flow = Rainfall Intensity x Total Area * Cr (1.3) + Total Base Flow

Determine Flow - The selected Calculation Method on the Pipe Sizing Criteria will then be used to establish the flow that the pipe/channel must have capacity to convey.
* Rational Method: Flow = Rainfall Intensity x Total Area + Total Base Flow
* (UK) Modified Rational Method: Flow = Rainfall Intensity x Total Area * Cr(1.3) + Total Base Flow
** Total Base Flow: Total base flow including all base flows from the upstream connections.​
** Cr = Retardance Coefficient​
*** Very smooth asphalt 0.007​
*** Tar and sand pavement 0.0075​
*** Concrete 0.012​
*** Tar and gravel pavement 0.017​
*** Short grass 0.046​
*** Dense grass 0.06​
** Rainfall Intensity:​
The Rainfall Intensity is determined from the IDF data, specified on the Pipe Sizing criteria , based on the Travel Time for the given connection. The Rainfall Intensity is then used in the selected Calculation Method to determine the Flow used for Auto Sizing the pipes/channels.​
Như vậy nếu chọn dòng chảy đều, với mạng lưới thoát nước nhánh cây thì thấy phần mềm InfoDrainage XPDRAINAGE đưa ra kết quả khác gì bảng tính Excel đâu ... việc gì phải mua phần mềm cho tốn tiền ... vì khi dùng phần mềm thì UK Modified Rational does not support Flow Diversions, Inlets, Storage Nodes, Pumps, Weirs, Orifices and Outlets.
 
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bachkcxbacninh

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Tẩu hỏa nhập khi đọc tài liệu hướng dẫn của Autodesk® Storm and Sanitary Analysis phiên bản 2020 bác @dotu2011xd @hienldvandon @dinhthanght ợ, nhiều thông tin trong đó là của phiên bản SWMM4 - đặc biệt là phần subcatchments, thông tin mốc xì, đọc vào đấy có mà "phúc thống phục nhân sâm" , với phần
"characteristic width of subcatchments" sai bét nhè ra, đúng là đồ tặng kèm Civil 3D nên Autodesk không quan tâm nhiều như Bentley.

Với phần lưu vực "subcatchments" của nó là "nonlinear reservoir routing of overland flow" , có bề rộng lưu vực "characteristic width" là một thông số chứ không phải là bề rộng địa hình như nhầm tưởng trước đây. Đặc biệt là "overland flow can be routed between sub-areas, between subcatchments, or between entry points of a drainage system", do vậy cần phải hiểu rõ.

Đọc kỹ lại mới biết cái "characteristic width = Characteristic width of the overland flow path for sheet flow runoff " được phần mềm ước tính ban đầu cần phải điều chỉnh lại "An initial estimate of the characteristic width is given by the subcatchment area divided by the average maximum overland flow length. The maximum overland flow length is the length of the flow path from the furthest drainage point of the subcatchment before the flow becomes channelized. Maximum lengths from several different possible flow paths should be averaged. These paths should reflect slow flow, such as over pervious surfaces, more than rapid flow over pavement, for example. Adjustments should be made to the width parameter to produce good fits to measured runoff hydrographs" cần được điều chỉnh. Vui lòng đọc thêm ở đây, nó khác hoàn toàn tính toán truyền thống như đã từng nghĩ trước đây.

ít nhất là phải ngồi lẩm bẩm bằng Excel đảm bảo khống chế overland flow tầm 150m
 
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tuank12agtvt

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Vô tình lướt qua, thấy đề tài khá hay dù mình thì chuyên nghiệp về giám sát cấp thoát nước, nhưng cũng đọc khá nhiều hồ sơ thiết kế, nhận thấy việc áp dụng mô hình SWMM5 vẫn đang có nhiều trở ngại lắm:
- Hầu hết đều cho kích thước cống tăng quá phi lý.
- Đường mực nước HGL không phản ánh đúng bản chất nếu lựa chọn cho phép ngập, đặc biệt là trên kênh hở
- Bề rộng lưu vực characteristic width of subcatchments là một tham số quá trìu tượng, đến nay vẫn chưa chốt hạ được như thế nào hết> Đọc tài liệu hướng dẫn chính thống của EPA cũng mơ hồ như một luận văn thạc sĩ (mục 3.8.4) https://nepis.epa.gov/Exe/ZyPDF.cgi/P100NYRA.PDF?Dockey=P100NYRA.PDF . Trên website https://openswmm.org/ đang xem đây là "The elephant in the living room question! - this is the elephant in the model room" . Lý do đây là việc xác định bề rộng lưu vực dựa vào khả năng chém gió của từng người "It is a empirical formula based on sensitive testing, experience, and comparison with Rational Method and flow data over the years". Do đó có thể nói SWMM5 chỉ nên áp dụng khi tính toán quy hoạch thoát nước cho khu đô thị hay khu dân cư mới thôi, vì khi quy hoạch thì mới có đầy đủ các thông số giả định, khi ứng dụng vào thiết kế chi tiết một hệ thống thoát nước sẽ không bao giờ có đầy đủ số liệu.
 

nghiepdtv

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Mô hình bản chất là mô phỏng, cũng như bất kỳ mô hình nào, mô hình thủy lực cũng phải đòi hỏi giả định xong kiểm nghiệm tiếp đến hiệu chỉnh, tiếp đến kiểm nghiệm, tiếp đến hiệu chỉnh ... đòi hỏi phát ăn ngay lấy đâu ra. Khi áp dụng bất kỳ mô hình thủy lực nào vào thực tế, đòi hỏi phải có kiến thức ở tầm chuyên gia chứ không phải kiến thức nghiệp dư, đừng mở mồm là tại phần mềm nó chạy ra kết quả như vậy thì như vậy nghe chối lỗ nhỉ lắm.

Mỗi mô hình mỗi phần mềm có những ưu thế riêng, có những nhược điểm riêng ... ngay kết cấu gọi là tường minh hơn nền móng hay thủy văn thủy lực mà cũng vậy, tính toán kết cấu bằng phần mềm này thì đạt, sang tính kết cấu bằng phần mềm khác thì không đạt ở một điểm nào đó, khi này năng lực của chuyên gia mới đóng vai trò quyết định. Ở bất kỳ quốc gia nào cũng vậy, chuyên gia luôn phải tự chịu trách nhiệm kết quả tính toán của mình, không đem quy chuẩn hay tiêu chuẩn ra để ăn vạ khi có sự cố hay tính toán sai.

Xét ở lĩnh vực thoát nước đô thị, trong điều kiện thiếu thốn dữ liệu đầu vào thì có thể áp dụng nhiều mô hình khác nhau, cộng với kinh nghiệm thực tiễn ở các đô thị tương tự với các hạng mục công trình tương tự để đưa ra quyết định quy mô kích thước công trình. Tuy nhiên đến thời điểm này, SWMM vẫn là mô hình duy nhất mô phỏng được thủy văn (quá trình hình thành dòng chảy trên các lưu vực thoát nước), thủy lực (dòng chảy ngược trong kênh hở, dòng chảy có áp trong cống, dòng chảy qua các cấu trúc thủy lực như đập tràn, máy bơm ....), do vậy vẫn là lựa chọn tốt nhất.

Xét riêng về SWMM, nếu không sử dụng phiên bản miễn phí thì hãy sử dụng các phiên bản thương mại chuyên về SWMM (SWMM-Based programs) như PCSWMM, GeoSWMM chứ đừng đi theo 3 thứ giả cầy nửa nạc nửa mỡ như SSA hay SewerGEMS, và điều quan trọng là phải có nền bản đồ GIS.
 
Đến nay vẫn chưa có bất kỳ một văn bản pháp lý nào để những nhà tư vấn có điểm tựa khi áp dụng mô hình EPA SWMM, cứ thử SWMM site:moc.gov.vn , SWMM site:xaydung.gov.vn trên Google là sẽ rõ, EPA SWMM hiện chủ yếu phổ biến trong giới hàn lâm và các khảo cứu đều mang tính trùm chăn và Google trong phòng máy, chứ chưa có khảo cứu thực nghiệm nào hết. Toàn dạng đề tài như thế này

Đánh giá hiện trạng làm việc hệ thống thoát nước thành phố Biên Hòa

Đọc xong toàn kiểu như hướng dẫn sử dụng phần mềm

Để ứng dụng rất cần những đánh giá thực tế về EPA SWMM và cách triển khai một cách có hệ thống.