Hydrological Evaluation of Septic Disposal Field Design in Sloping Terrains

Design and risk assessment tool for vegetative treatment areas receiving agricultural wastewater: Preliminary results

“…The purpose of the model is to serve as a tool for VTA design, site evaluation, and surface discharge risk assessment. The existing model framework was originally developed by Collick et al (2006) for on-site septic systems, and is applicable on slopes greater than 2%. USDA-NRCS (2006) recommends that VTAs be installed on slopes between 1% and 5%.…”

Real-Time Forecast of Hydrologically Sensitive Areas in the Salmon Creek Watershed, New York State, Using an Online Prediction Tool

“…The water balance model integrates several concepts presented in the following sub-sections. For a more detailed description of the model and its modifications see [19,24,25]. For watersheds dominated by saturation excess overland flow, Steenhuis et al [49] showed that the fraction of the watershed that produces runoff (A f ) can be estimated from the ratio of the change runoff depth (ΔQ) to change in precipitation depth (ΔP).…”

“…Thus, it is designed for applications in watersheds dominated by saturation-excess overland flow. The model has been developed and tested in various VSA hydrology-dominated watersheds [18,19,[24][25][26]. The model operates on a daily time step and uses readily available inputs such as daily precipitation, minimum and maximum temperature, as well as topography (digital elevation model) and soil characteristics (soil depth and saturated hydraulic conductivity) to distribute and locate saturated areas in the landscape with the soil topographic index [10,18,25,35,[52][53][54][55].…”

“…HSAs are areas that saturate or generate saturation excess more often than some threshold (e.g., more than 30% of the days in a month). Previous efforts to identify HSAs have largely used distributed hydrological models such as SWAT-VSA (Soil and Water Assessment Tool re-conceptualized for VSA) [18,19] and the VSA water balance model [19,[24][25][26][27]. Managers could potentially use the HSA concept to identify areas that are more likely to saturate or that are more hydrologically sensitive so that these areas could be protected from potentially polluting activities, such as animal manure applications to agricultural land (e.g., [9,22,28,29]).…”

“…The tool is designed to assist producers and planners in making daily decisions by quickly identifying fields or portions of fields at high risk of generating storm runoff (i.e., HSAs), so that those areas can be protected from potentially polluting activities (e.g., manure, fertilizer or pesticide applications). The HSA prediction tool is intended for application in watersheds characterized by saturation-excess runoff generation, as is common in the northeastern U.S. HSA predictions are made using real-time measured Northeastern Regional Climate Center (NRCC) meteorological data and 24-48 h temperature and precipitation projections from the National Oceanic and Atmospheric Administration Global Forecast System Model Output Statistic (NOAA GFS MOS) ensemble data in a water balance model developed for VSA hydrology-dominated watersheds [24,25,49,50]. This ensures that locations and the timing of storm runoff generation are accurately predicted based on current moisture conditions rather than based on long-term average conditions such as the soil's flood frequency class or drainage class as currently used in the NYS P-Index [9,22,35].…”