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

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

    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 mưa4.2.2 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);

    Td - 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

  • #2
    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.

    Comment


    • #3
      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.

      Comment


      • #4
        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. (http://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.

        Comment


      • #5
        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

        Comment


        • hoangdung
          hoangdung commented
          Editing a comment
          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

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