Browsing by Subject "Drainage"

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    Assessment and Recommendations for the Operation of Standard Sumps as Best Management Practices for Stormwater Treatment (Volume 2)
    (Minnesota Department of Transportation, 2012-05) McIntire, Kurtis D.; Howard, Adam; Mohseni, Omid; Gulliver, John S.
    In order to improve the performance of standard sumps as a best management practice (BMP) in treating stormwater runoff, a baffle was designed to be installed as a retrofit in standard sumps. The retrofit is a porous baffle called “SAFL Baffle”. The effect of the SAFL Baffle on the performance of standard sumps was assessed by conducting laboratory tests on small scale as well as full scale straight flow-through standard sumps equipped with the baffle. In addition, a number of tests were conducted to determine the performance of standard sumps with the SAFL Baffle when the baffle is clogged with debris like trash and vegetation. Furthermore, the performance of two other configurations of the baffle was studied: (1) the SAFL Baffle in a sump with an outlet pipe 90 degrees to the inlet pipe, and (2) the SAFL Baffle in a sump with some water entering the sump through an overhead inlet grate. Standard sumps equipped with the SAFL Baffle were evaluated using two metrics: (1) How well the system captures sediment during low flow conditions (Removal Efficiency Testing), and (2) how well the system retains the previously captured sediment during high flow conditions (Washout Testing). The results of the tests showed that the SAFL Baffle dissipates the energy of water entering the sump and as a result, at low flow rates, it captures sediment better than a standard sump with no baffle. More importantly, at high flow rates, the washout of the previously captured sediment reduces to near zero.
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    Comparison of Evapotranspiration Estimation Methods and Implications for Water Balance Model Parameterization in the Midwestern United States
    (2019-12) Talbot, Michael
    Evapotranspiration is the second most dominant component of the global water cycle behind precipitation, yet it remains one of the most difficult to measure and model. The numerous methods that have been developed for estimating evapotranspiration (ET) rates using climatological data vary in both complexity and spatiotemporal robustness. While the Penman-Monteith method has continually been shown to compare better with observed ET rates across more geographies and timescales than any other method, its high data requirements remain a barrier to use in many areas, and it is often desirable or necessary to make use of an alternative method. Daily reference ET estimates from the Penman-Monteith method were compared to ET estimates from seven alternative methods, which were generated using 14 years of observed weather records at five locations across the Midwestern United States. Then, a one-dimensional water balance model, DRAINMOD, was run at 362 locations across the Midwest using 50 years of synthetic climate data and three distinct sets ET inputs: 1) reference ET from the Penman-Monteith method, 2) potential ET generated from the Penman-Monteith reference ET and location-specific crop coefficient curves, and 3) potential ET from the Thornthwaite method. Results suggest that the best alternative method to Penman-Monteith varies by location, application, and timescale of interest, and that the misapplication of ET estimates for water balance model parameterization could have a dramatic impact on the accuracy of model predictions.