Impervious cover are impermeable surfaces, such as pavement, sidewalks and rooftops that prevent the infiltration of water into the soil. Limiting impervious cover reduces water runoff and helps maintain water quality in the Highland Lakes because more water is absorbed into the ground. Water runoff is the single largest source of pollution in the Highland Lakes.
Developers and builders earn stormwater credits that can help gain compliance with the alternative standards in the Highland Lakes Watershed Ordinance by using conservation landscaping, and other methods, such as porous pavement, preservation of natural areas and rainwater harvesting. These alternative standards allow them to avoid constructing expensive water-quality basins to capture runoff. See section four of the LCRA HLWO technical manual.
Conservation landscaping is one of the primary ways to earn stormwater credits. It involves using limited turf area, preserving natural vegetation and planting native trees, shrubs, and perennials to filter stormwater runoff and minimize the use of chemicals. These practices are well-known ways to reduce stormwater runoff and to improve the quality of the water running off a development.
There are four major components that increase landscape sustainability:
- Adequate quantity of high quality soil
- Implementation of efficient irrigation
- Appropriate turf and plant choice
- Proper installation
For more information on stormwater credits, Contact LCRA or call 512-473-3200, ext. 2091.
Excel worksheet to calculate water quality volume and the size of permanent water quality management features under the Highland Lakes Watershed Ordinance