Pathway to Safe, Clean Water in the Upper LA River

Capture and treat runoff before it reaches the river.

How do we decide where to invest these resources?

A Stormwater Investment Plan ("SIP" for short) is a financial strategy that prioritizes where and when stormwater projects should be built. The SIP identifies potential project sites, evaluates project costs and impacts, and charts implementation schedules.

The Upper LA River Watershed Group's current Watershed Management Program (WMP) recommends over 10,000 potential stormwater projects, with a price tag of $6.4 billion - that would take 90 years of Safe Clean Water Program SIPs! But the WMP doesn't say where to build all of those projects...

So, a scientific study was proposed by the Watershed Group, in partnership with the San Gabriel Valley Council of Governments. Seeing the value, the study was funded by the Safe Clean Water Program's  Upper LA River  and  Rio Hondo  Watershed Area Steering Committees.

We're calling it a "pre-SIP."

A project is not just a point on a map: it is a physical alteration of city infrastructure and natural landscape. Real project opportunities require real engineering expertise paired with political savvy and community knowledge. Our approach leverages all of these elements to prioritize project opportunities with existing momentum and a high chance of success.

Watersheds are complex systems. Make one change upstream, and the impacts cascade down. Our approach was to develop an updated, site-specific watershed model for the Upper LA River and ground-truth it with local monitoring data. This model could then be used to predict not only the impact of individual projects, but the impact of a whole system of projects on pollutants like...

Heavy Metals: Zinc is a limiting pollutant in the Upper LA River Watershed. If we can implement projects that address zinc, they will also address other heavy metals and sediment-borne pollutants in the process.

Bacteria The Watershed Management Group is taking additional steps to reduce bacteria in the Upper LA River. In 2022, the Group began implementing a groundbreaking Load Reduction Strategy (LRS) Adaptation that aims to target and eliminate potential sources of disease-causing bacteria. Learn more about the LRS Adaptation  here .

The list of potential projects is long: our screening process identified opportunities with the greatest chance of impact.

Our engineering team narrowed these down to 650 for modeling.

At its core, our watershed model simulates storm events and predicts associated pollutant loads.

Potential stormwater projects can be "dropped" at any point in the watershed model, and their collective impact on downstream water quality can be simulated against important metrics like project size and cost.

✅REALITY CHECK: To ensure predictions confidently reflect local realities, the watershed model was calibrated using new data from monitoring stations throughout the Upper LA River Watershed to meet the rigorous standards of the LA Regional Water Quality Control Board. These monitoring stations can also be used to validate the model as projects are implemented and to inform the adaptive management process as changes arise. For more details, please review this  Baseline Model Summary Memo .

The StoryMap below presents one potential pathway to meeting pollutant reduction targets in the Upper LA River Watershed (click the arrow to surf the watershed).

But, there are many pathways to safe, clean water in the Upper LA River...

First, stakeholders have to answer the tough questions:

To test how different priorities point us towards different projects, the preSIP team generated several different pathways to achieve alternative definitions of clean water allowed by regulations. Compared to the Upper LA River Group's current Watershed Management Program (WMP), the preSIP provides more achievable, affordable, and actionable pathways to clean water.

What projects make up these pathways and which project should you pick first?

The ULAR dashboard is here to help.

ULAR preSIP DASHBOARD = A Sandbox for Stakeholders

While the maps above present different pathways to clean water, they are just a snapshot in time. Project details and status can change from week to week, so agencies need a way to actively maintain the preSIP project library and coordinate to achieve watershed-scale success.

The preSIP study provided each agency in the Upper LA River Watershed Group with access to a web-based platform where they can centralize all of their project details and track relative progress. Project information can be updated as projects advance towards completion, and new projects can be added for the whole group to see.

Now agencies can play out stormwater scenarios and use the results to achieve what the Upper LA River needs most...

Throughout the study, the preSIP team engaged 28 partner organizations to learn about their Upper LA River projects and initiatives... but we know we didn't reach everyone.

Do you have a project idea you'd like added to the preSIP?