A Creative Alternative to a TMDL to Address Eutrophication in Loma Alta Slough
Eutrophication in Loma Alta Slough is most evident in the late summer months, as green algal mats cover much of the surface of the waterbody. Since 2006, the Regional Board and stakeholders in the Loma Alta Watershed have been working together towards a total maximum daily load (TMDL) to address eutrophication in the Slough. The process began in 2007-2008 with intensive monitoring to collect data to support a TMDL, followed by scientific assessments of the data and modeling to determine targets and wasteload allocations, punctuated with the development of a draft TMDL in early 2014. In the meantime, the State has been developing nutrient numeric endpoints that may be more appropriate for the Slough than the existing water quality objectives in the Basin Plan. Despite the improving science, the Regional Board was compelled to finish the TMDL, but was willing to consider creative alternatives if possible.
The starting point was to identify the key needs of each stakeholder and the constraints of the regulatory process. Understanding the overlapping needs, the stakeholder group explored multiple regulatory options including the traditional TMDL approach, a single regulatory action, another investigative order, category 4B, and implementation via existing MS4 Permit requirements. Ultimately, the Regional Board chose alternative process to address the impairment in the Slough that relies on the effective prohibition of non-stormwater discharges and development and implementation of a watershed based Water Quality Improvement Plan (WQIP) as required by the recently adopted MS4 Permit.
The purpose of the talk is to focus on the collaborative stakeholder process used to develop a creative alternative to the TMDL, including the end goals for each stakeholder (City of Oceanside, Regional Board, USEPA), the various alternatives that were considered, the resulting Resolution that was adopted in lieu of a traditional TMDL, and the path forward for implementation and adaptation. The discussion will be relevant to municipalities and regulators that are looking for better integration of TMDL programs with MS4 Permit requirements. The topic is especially timely as TMDLs are becoming more common and MS4 Permits are moving towards prioritization of water quality problems and watershed based approaches. The talk will highlight benefits of an alternative process and cover the collaborative adaptive management process moving forward.
This talk is directly supportive of theme of “Are We Making a Difference?” as it will address three key areas where we were successful and are making a difference. These include: (1) a more efficient, streamlined regulatory process that will lead to quicker implementation and achievement of goals, (2) watershed based implementation that dovetails with MS4 Permit requirements, fostering a better use of limited resources, and (3) a well-defined collaborative adaptive management process that allows stakeholders to assess progress and determine the best path forward to solve the eutrophication problem in Loma Alta Slough.