Building Momentum for Green Infrastructure Implementation in North Texas (Part 1 of 2)
Stage four water use restrictions are looming in North Texas. Our reservoirs are at 25% of capacity. Emphasis on water conservation is an obvious need and we have generally adapted to the restrictions. We are getting used to them. Water quality is a different story. I firmly believe that protecting the quality of the water that we are in such short supply should be a top priority. Storm water management has traditionally been considered from the perspective of managing the quantity and reducing flood risks. While this will always be necessary, we need to understand that managing the quality of our storm water runoff is equally important. Where do we stand today and what do we need to do to move the needle toward improved water quality? I'll explore our current situation in this blog entry and discuss how we can start moving towards a cleaner water future that everyone will benefit from in future posts.
The U.S. EPA proposed a new regulation to make changes to the existing Municipal Separate Storm Sewer System (MS4) permit requirements in December 2009. The proposed changes sought to reduce the quantity and improve the quality of storm water discharges from both new development and redevelopment areas within the regulated MS4 areas. The hope was that these changes would serve as a catalyst for broader implementation of green infrastructure and low impact development strategies. The reality was that after the MS4 general permits were renewed in 2010, few changes were made in development requirements. Consequently, there was only a slight uptick in projects that applied these strategies.
The list of impaired water bodies in Texas continues to grow, while the implementation of green infrastructure strategies for new development and redevelopment continues to stall. The Texas Integrated Report of Surface Water Quality is a biennial report that satisfies the requirements of the federal Clean Water Act Sections 305(b) and 303(d). The 303(d) list categorizes impaired water bodies that do not meet applicable water quality standards or is threatened for one or more designated uses by one or more pollutants. Most of the water bodies listed are trending toward the category 5(a) designation that total maximum daily load (TMDL) studies are underway or about to be implemented. The Trinity River between its confluence with the Elm Fork and Five Mile Creek on the downstream end is one such water body with a TMDL study for bacteria underway. A TMDL is the calculated maximum amount of a pollutant that a water body can receive and still meet the water quality standards.
The TMDL designation also requires that an Implementation Project or "I-Plan" be developed which describes both voluntary and regulatory management measures required to restore the water quality of the impaired water bodies to a level suited for its intended use. The Greater Trinity River Bacteria TMDL I-Plan affects an area of 406 square miles and a population of 1.33 million. The impacted areas do not meet water quality standards for recreational use due to elevated bacteria concentrations. Multiple pollutant sources have been identified, both point and non-point sources. Sanitary sewer overflows and storm water runoff are two major contributors identified in the I-Plan. Participation in the I-Plan at this point is voluntary and a list of priority implementations are provided with some very conservative time frames. The top three implementation strategies relate to improvements in sanitary sewer overflows and storm water management.
The implementation strategies at this point essentially direct MS4's to keep doing what they are doing and to possibly implement development standards that will treat the storm water runoff from new developments. We've been implementing these strategies for more than a decade and it's becoming evident that these strategies need to be revisited. Although only two creeks and one segment of the Trinity River have voluntary TMDL's, the vast majority of the remaining water bodies and creeks in North Texas are listed as having varying degrees of concern for bacteria, pH, low dissolved oxygen and habitat impacts. The latest list of water bodies and streams with concerns can be downloaded from TCEQ at this link: Water Bodies with Concerns for Use Attainment and Screening Levels. The list is very long and it is a very strong indicator that we need to address pollution of our creeks, lakes and rivers from untreated storm water runoff and aging sanitary sewer conveyance systems. The good news is that there is a smart way to do this that will benefit the quality of life and the economy in North Texas. I'll discuss it in my next entry.