Water balance and infiltration testing
Water balance is the hydrologic cycle of precipitation, groundwater infiltration, evapotranspiration and run-off. Urbanization can cause changes to the hydrology of natural features such as wetlands, woodlands and watercourses. The pre-development and proposed post-development conditions of the subject property are characterized, and the changes in water balance are calculated.
Low Impact Development (LID) measures are recommended where development without LID measures would result in negative effects. LID measures can include infiltration galleries, permeable pavers, increased topsoil thicknesses and selection of permeable backfill. In-situ testing of infiltration potential in the proposed location of LID features is undertaken.
Stream baseflow, determination of wetland feature limits, catchment limits and recharge (infiltration) areas are identified. Where wetland features are present, a comparison of the wetland feature and catchment area hydrological criteria conditions for pre-development and post-development conditions, and overall measure of hydrological change are prepared.