The McKale Memorial Center sports complex on the University of Arizona campus is subject to some flood risk. The Surface Water Working Group (SWWG), a group dedicated to reducing stormwater (surface) flows on campus, identified this specific flooding problem for the SWES399/599 class project. The aim is to develop a suite of solutions to reduce flood risk, including the appropriate introduction of rainwater harvesting interventions. Working with the SWWG, Facilities Management, and Brad Lancaster the class identified a number of interventions which in combination might help reduce surface water flows that accumulate in a low point on Enke Drive south of the McKale Memorial Center. These interventions are located on an orthophoto of the site.
The class decided to focus on one set of interventions along the Martin Street corridor (point #2 on the map). This sub-project will be completed in three stages.
Stage 1: a traffic table will be constructed across Enke Drive in line with the Martin Street sidewalk. This raised crossing will act as a berm preventing westward surface water flows.
Stage 2: will direct this stored surface water from Enke Drive into a swale with a series of gabions running east of the Martin Street sidewalk. The swale and gabion construction will allow water to infiltrate into the soil providing soil moisture for pine trees on the west side of the side walk. (The area was blue staked to identify all buried utility lines).
Stage 3: will direct overflow into a series of basins around the pine trees on the west side of the Martin Street sidewalk.
Two prerequisites for engineering the swale for flood conditions were: conducting a detailed site survey (1/2 inch resolution); and estimating water flows along the swale. This latter exercise was completed by two graduate hydrology students. They used watershed maps, 10-year and 100-year flood conditions, and Manning’s equation to calculate surface flows in cubic feet per second (cfs) at the site.
