SWMM model files for Minebank Run, Baltimore, MD (As-is, ESD, Ponds)

Minebank Run watershed is located in Baltimore Co., Maryland and drains parts of Towson, MD. Development within the watershed started in the 1930s and accelerated in the 1950s and 1960s. Most of the developed area was built prior to the development of stormwater management regulations. A SWMM model was developed for Minebank run to simulate runoff resulting from 5-minute rainfall for the period of 1948-2001. Hourly precipitation records were available starting in 1948 and were disaggregated in order to run the SWMM model on a 5-minute basis. Land cover changes were studied using historic aerial photographs and satellite imagery of the area and shapefiles of structures and roads provided by Baltimore County. The GIS data obtained from Baltimore County reflected the most up-to-date ground conditions. The historic aerial imagery were used to eliminate structures from undeveloped areas working backward in time from the county GIS data to reflect conditions on the ground during each land cover period. Existing stormwater management practices consisted mostly of detention ponds. Five such ponds were identified in the Minebank Run watershed that were large enough to potentially cause an impact on a watershed level. Detention ponds are represented in SWMM by developing the depth-surface area curve and determining the type, size, and elevation of the outfalls. Multiple outfall types exist for each pond including weirs and pipes. The SWMM model was calibrated for water year 2018 and validated for water year 2012.