Case Studies on the Effectiveness of Typical Regulations for Detention Storage

Steven F. Albert, P.E., CFM

Regulations established mandating detention storage to mitigate for increased runoff from land development often do not work as intended. Typical regulations can be made more effective by overcoming their limitations to maximize the value of the detention storage volumes created under these regulations. Two case studies will be presented to report the results of research undertaken for the Harris County Engineering Department. The first study is an examination of the impact of ordinances mandating a minimum size for outlet control restrictors. This policy results in detention storage that is not fully used during design storm events. The results document this impact for watersheds up to 5 acres and presents the simple restrictor sizing tool developed to replace the use of minimum orifice sizes and to eliminate use of the orifice formula for outlet sizing. The second study relates to the design of pond outlet control devices. Maximizing the allowable site release rate through the lowest pond outlet restrictor fails to maximize the holding time of stormwater in the basin. Changing the location of the allowable pond release rate from the bottom to the top of the basin using multi-stage orifices and overflow spillways increases pond effectiveness measured in acre-foot-hours of storage.

Presented by, Steven F. Albert, P.E., CFM

Steve Albert serves as the Vice President of Infrastructure for Binkley & Barfield Engineers in Houston. He has practiced civil engineering for 41 years with the past 19 years focused on the effective application of Low Impact Development (LID) stormwater practices. Current responsibilities include serving Harris County Engineering as their LID on-call consultant. Steve has extensive experience in land development, water and sanitary sewer systems, and stormwater management design and modeling.

Steve is a registered Professional Engineer in several states including Texas, Louisiana, and Oklahoma and is a Texas Certified Floodplain Manager. He is a Texas Certified Floodplain Manager. Steve serves as an Advisor to the Houston Land/Water Sustainability Forum and recently completed six years as the Sustainability Chair for the Houston Branch of ASCE. He frequently makes presentations to municipal and professional groups on the cost-effective use of LID methods.

Steve holds a BS degree in Civil Engineering from the University of Illinois and a Master of Management degree from Northwestern University.