Use of Continuous Simulation for Evaluation of Stormwater Management Practices to Maintain Base Flow and Control Erosion

Model application to assess effects of urbanisation and distributed flow controls on erosion potential and baseflow hydraulic habitat

“…Usually, in such models low-impact distributed flow controls are lumped together in large devices, and conventional devices such as ponds are used to represent low-impact devices approximately (e.g. Guther et al 1996). More recently, a few models have been developed to represent distributed low-impact drainage devices explicitly (Pitt and Voorhees 2000, Wong et al 2002, Zhen et al 2004, Elliott et al 2009.…”

“…The 2-year return period flow rate is often used to indicate stream morphology effects (Leopold 1994, Roesner et al 2001. Considering that erosion is related to the duration of high flows as well as magnitude (MacRae 1997), other metrics have been used such as the duration of flows above a critical threshold (James 1995, Guther et al 1996, Rohrer and Roesner 2006 or bedload-transporting capacity integrated over a design storm event (MacRae 1997, Bledsoe et al 2007). Mecklenburg and Ward (2002) extended the latter approach to include a range of design events and their associated probability of occurrence.…”

Calibration of BASINS HSP-F in Support of a Watershed Approach to CSO Long Term Control Planning

“…The NPSM (Nonpoint Source Model)/HSP-F model in the BASINS system, version 2 was used for this project. Subsequent to the project completion, BASINS version 3 was released and HSP-F within the newer version is referred to as winHSP-F. A literature review was conducted to help identify appropriate parameters for a sensitivity analysis (Laroche et al, 1996;Fontaine and Jacamino, 1997;Jacamino and Fields, 1997;Guther et al, 1997;Srinivasan et al, 1998;Carrubba, 2000;Lee, 2000) and using a continuous modeling approach and daily mean flow for the period May 1 through October 31, 1990, it was determined that the parameters USZN (upper zone nominal soil moisture storage) and LZSN (lower zone nominal soil moisture storage) had the greatest influence on daily mean flow, particularly in relation to storm event peak and volume. The parameters AGWRC (basic groundwater recession rate) and INFILT (index to infiltration capacity) tended to have the greatest impact on baseflow characteristics.…”