Baltimore Ecosystem Study Cary Institute of Ecosystem Studies

2012 BES Annual Meeting Presentation and Poster Abstracts

Quantifying discharge of headwater tributaries across a range of development patterns and stormwater management conditions
Grazia, Eric
Co-Authors: Eric Grazia, Claire Welty, Andrew Miller, Edward Doheny, Rose Smith, Sujay Kaushal, Michael Pennino, and Michael Barnes

Abstract: One of the goals of the NSF Baltimore Water Sustainability and Climate project is to examine the effects of stormwater management and development age and pattern on coupled groundwater-surface water flow regimes and nutrient export. Our premise is that watersheds at the subdivision scale are the basic units of hydrologic analysis in the suburban landscape. To this end, we have recently instrumented six tributaries draining areas ranging from 0.21 to 0.63 sq km in the headwaters of Dead Run and Red Run. Sites span residential and commercial land use; stormwater management ranges from none to a combination of dry/wet detention and infiltration. We are measuring flow immediately downstream of stormwater management features or storm drain outfalls. In tributary watersheds lacking stormwater management we are measuring flow draining from a comparable-area headwater subbasin. There are some fundamental technical challenges to establishing flow records in very small urban watersheds. Measurement of base flow is especially difficult at sites where water depth cannot accommodate a velocity meter. We are incorporating dilution gaging, area-velocity measurement devices, volumetric flow measurements, and other creative approaches to help us improve the accuracy of our baseflow measurements. Stream flow data from these stations will be used in conjunction with high-resolution ParFlow modeling to test hypotheses about system behavior and response to both climate and land-cover change over event, seasonal, and annual time scales.