Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Innovative Monitoring to Support Management Objectives in a Complex Subwatershed
Brown and Caldwell, United States of America;
The Ada County Highway District (ACHD) in Boise, Idaho manages a 58,000-acre Phase I MS4 permit area. One of the largest and most complex subwatersheds in the permit area is the 900-acre Americana subwatershed. If you can think of a stormwater management challenge, there's a good chance it is represented in this subwatershed, and outfall monitoring alone does not provide the resolution necessary to support management objectives in this highly dynamic, mixed use drainage area.
Water quality and quantity challenges in the subwatershed include groundwater infiltration, construction and redevelopment in the downtown area, aging infrastructure and high nutrient loading in the residential areas, irrigation spillbacks, and disposal of high groundwater from sumps, utility vaults, and footing drains. In 2018 ACHD began deploying level monitoring equipment in short-term installations throughout the subwatershed to help quantify flows from various subcatchments to better understand sources of wet weather and dry weather flows.
This presentation will discuss how pairing low-cost subcatchment monitoring with permit-required outfall monitoring has resulted in the following outcomes:
more accurate model validation
increased illicit discharge detection and pollutant source identification
improved management of authorized non-stormwater discharges
more representative stormwater quality sample collection
8:45am - 9:30am
Hawaiian Watershed Water Quality Modeling Using HSPF
Stephen Blanton, Yacoub Raheem
AECOM, United States of America; ,
A privately owned lake in Hawaii that receives surface water runoff from the local jurisdiction has experienced water quality issues for many years. The owners of the lake have asked the jurisdiction to implement stormwater best management practices (BMPs) throughout the 3,350 acre watershed in order to reduce total suspended solids (TSS) and nutrients from entering the lake.
A multi-year water quality sampling effort was conducted to better understand the volume of material entering the lake and also identify potential sources. The sampling efforts provided potential calibration data related to flows and pollutants.
The Hydrological Simulation Program - FORTRAN (HSPF) was used to develop a model of the watershed using local soils and land use data. The HSPF model was calibrated to flows recorded at the water quality sampling sites. Following the hydrologic calibration, the HSPF model was calibrated for TSS and nutrients, using estimated target loadings and the measured water quality concentration data.
Using the calibrated model, annual pollutant loadings to the lake were estimated based on land use. Potential BMPs were identified to reduce the pollutant loadings. This effort also included estimating the implementation cost for the recommended BMPs.
This presentation will look at the challenges of hydrology and water quality calibration of an HSPF model in Hawaii, where watersheds are affected by micro-climates.