6.1 Regulatory Program
Future development in the watershed is expected to impact water and other natural resources in the watershed. Land use change when not done properly impacts downstream water quality by increasing the volume of runoff and the concentration and load of nutrients and sediment transported to receiving waters. Each subwatershed plan contains an analysis of the expected impact of future development on the water quality of lakes within the subwatershed, assessing both the expected 2020 conditions and potential Ultimate Development conditions. While the current regulatory program requires developers to pretreat runoff to reduce of some of that new nutrient load, that amount of nutrient removal will not be sufficient to prevent future degradation of water quality.
Development has other impacts as well. New impervious surface such as roads, driveways, roofs, and parking lots increases the volume of stormwater that runs off the land. This volume flows to lakes, streams, and wetlands, carrying with it nutrients and sediment. The increased volume can impact peak flows in streams and channels, and increase the duration of peak flows, potentially causing erosion. Additional volume discharged to wetlands can change water levels and the amount of time vegetation in wetlands is inundated, altering vegetation and impacting ecological integrity of those resources.
Groundwater can be impacted by development as well. Changing stormwater runoff patterns can reduce the amount of stormwater that natural percolates into the soil, altering local surficial aquifers and impacting wetlands, baseflow in streams, and in time the deeper aquifers.
To mitigate these future impacts, the District will consider additional regulatory controls on permitted development and redevelopment. These controls are part of the District’s integrated, performance-based strategy that links regulation, programming, and capital improvements to the achievement of specific management goals by subwatershed.