Alternate: Stormwater and Nature-Based Solutions, Using all of the Tools in the Toolbox

Nutrients and sediment are consistently identified as major contributors to water quality impairments and have resulted total maximum daily loads (TMDL) being developed for numerous water bodies. Theoretically the TMDL will include allocations for point sources and nonpoint sources with expectations for reductions of nutrient and sediment loads. The primary source of these pollutants is open to debate; however, publicly owned treatment works (POTWs) and urban/suburban stormwater discharges are known contributors of nutrient and sediment loads along with agriculture nonpoint sources (NPS). There is no mechanism to easily address nonpoint sources, so the focus immediately centers on the point sources. This focus then leads to lower limits for publicly owned treatment works (POTWs) regardless of whether that source is a significant contributor, and increasingly, MS4 permits also include difficult to achieve nutrient limits. In the case of the POTW, the lower limits then require the POTW to consider additional treatment which often includes increases in energy and chemical costs. Urban and suburban areas are also a focal point for growth and development which will require planning to address increased pollutant loads, and development will have impacts upon water resources which leads to the need for mitigation (Clean Water Act (CWA) 404 permits) and construction stormwater permits. The USEPA has a long history of supporting water quality trading and made it clear that one of the ways to achieve water quality standards and water quality-based limits is through trading (USEPA 2003, 2009, 2019). Despite this strong support, trading is only used in a few states and generally is only in the form of point source to point source trading. In places where it is used it has been quite successful, Virginia's Nutrient Exchange is a very good example, though it is primarily point to point trading. This minimal use of an effective tool raises the question of why its use is so limited and how might this be changed. Given the need to address pollutant loads from nonpoint sources, trading needs to be expanded to incentivize point to nonpoint trading. Clean Water Act section 402 provides the primary driver for control of stormwater discharges. The specific control mechanism is the NPDES permit and owing to that fact the controls are focused on water quality rather than quantity. This focus has been emphasized in litigation where the courts have ruled that quantity of water is not a 'pollutant' and therefore cannot be directly limited in a NPDES permit. Stormwater discharges result from many different activities: runoff from municipal surfaces, industrial sources and also from development activities. In the case of development activities, depending on the location of the development and the impact on water resources a CWA 404 permit may also be required. This brings us to the intersection of urban/suburban development, stormwater, mitigation and the need to reduce discharges. Stormwater discharges are primarily regulated under CWA section 402 while compensatory mitigation is under CWA section 404. Section 402 focuses on pollutants while section 404 focuses on adverse physical impacts to aquatic resources. One potential adverse impact is related to quantity of flow. Quantity of flow has a direct connection to water quality given the fact pollutant load is directly impacted by the volume of flow. Flow reduction means reduction in pollutant load. Depending upon the size of the municipality, there could be hundreds or thousands of individual outfalls. Putting treatment on each outfall is physically and economically impossible. Also, as touched upon earlier, these may not be the largest source of the pollutants. This issue of the need to focus on the largest sources, not just the point sources was highlighted almost twenty years ago in a watershed-based approach by Clean Water Services in Oregon. The issue was temperature impacts and the cost of reducing temperatures at the wastewater treatment plant, a small point source, versus solar radiation impacts on the large land areas (nonpoint sources) ' see Cochran and Logue 2010. It has been shown over and over that focusing on point sources is not going to solve the problem. The solution is a watershed-based approach and that means point sources and nonpoint sources working collaboratively. A potential common thread between nonpoint sources, 402 permittees and 404 permittees are the use of green practices to achieve compliance. This is bolstered by the recent policy position of White House for the use of 'Nature-based' solutions ' see - https://www.whitehouse.gov/briefing-room/statements-releases/2022/11/08/fact-sheet-biden-%E2%81%A0harris-administration-announces-roadmap-for-nature-based-solutions-to-fight-climate-change-strengthen-communities-and-support-local-economies/ The White House position notes that, 'Few know that nature-based solutions can help address common problems, like coastal flooding or urban heat islands.' As noted earlier, controlling volume will also provide positive impacts regarding water quality by reducing the pollutant load. Similarly, addressing flooding addresses pollutant load, so the key is to look for opportunities to build projects with multiple benefits. The presentation and manuscript will include a discussion of similar but different approaches used for green approaches and the way quantity and quality can interact, specifically, controlling quantity controls mass of pollutants and leads to improved water quality. The presentation will include a number of examples where ecological restoration projects have addressed NPDES permit requirements as well as providing numerous ancillary benefits. The presentation will also include a discussion of the need to address both runoff and instream impacts that deliver pollutant loads into the downstream waters. It is also important to note that controlling quantity of water also provides opportunities to address flooding concerns which are not a driver associated with NPDES permits. While looking at the issues involved with needing to comply with permit limitations established to be consistent with assumptions of applicable TMDLs, the presentation will also consider the impact of CWA section 404 compensatory mitigation that arises as a result of projects that have potential to impact water resources. Compensatory mitigation may also be needed in order to address impacts due to stream restoration or other instream projects done to meet stormwater requirements and/or TMDL reductions. The presentation will also discuss how lessons learned in the compensatory mitigation program may be applied to make better watershed-based approaches more successful by including a specific set of options and practices similar to what is done to meet 404 permit requirements.