Central Coast MS4 Tool Development

The Central Coast RWQCB, Low Impact Development Initiative and the Central Coast municipal partners are collaborating with 2NDNATURE, LLC to develop tools to maximize and track stormwater program effectiveness. The tools of the MS4 Support Project are intended to guide yearly prioritization of actions to reduce urban pollutant loading and to simply communicate the effectiveness of those actions. In addition, the products generated will allow municipalities to meet a number of Phase II MS4 permit requirements.

Rather than focusing on modelling and monitoring potential receiving water responses to management actions, the MS4 Support Project focuses on monitoring and modelling the urban landscape to derive relatively accurate estimates of volume and sediment reductions resulting from management actions.

The monitoring includes the inventory and assessment of structural BMP condition over time using a BMP Rapid Assessment Methodology (BMP RAM). The modelling is conducted using a computationally refined urban hydrology and pollutant loading model – Tool to Estimate Load Reductions (TELR) – developed to estimate the relative expected benefits of stormwater management actions implemented within urban catchments. Rather than modelling pollutant by pollutant, TELR uses volume and sediment as the representative proxies to represent the fate and transport for the majority of traditional urban stormwater pollutants. A number of simplifying assumptions are used regarding the fate and transport of urban stormwater and associated particulates that we believe will successfully guide stormwater program managers in prioritizing where to implement improvements and track the effectiveness of those improvements. The approach is transparent and aims to put cost-effective tools directly into the hands of the stormwater managers and their staff.

The MS4 Support Project provides an easy to use, comprehensive, data management system that allows annual iteration of tasks to continually inform where limited resources would be best spent; communicate the estimated water quality benefits of actions implemented; and meet ongoing stormwater permit requirements. These tools will be available to any municipality in late 2016.

To learn more about TELR, BMP RAM and follow progress of full stormwater tool development visit our STAKEHOLDER INFORMATION sharing site.