Freeways, roads and buildings in the hilly landscape of Northeast Los Angeles.
Urban Conservation View from Elysian Park, Northeast Los Angeles. © Steve & Julie/Flickr

Stories in California

Urban Conservation: Pioneering Solutions in Los Angeles

TNC is working in Los Angeles to demonstrate what nature can do for cities—and what cities can do for nature.

Though California is known for its iconic natural beauty, nearly 95% of our state’s residents currently live in urban areas. In the coming years, billions of dollars will be invested to upgrade infrastructure in the urban environment. We have the opportunity to bring nature into this development.

TNC works with natural infrastructure—infrastructure based on natural systems and processes—to transform critical elements of city life, like the way stormwater is managed to help address Los Angeles’ water quality and water supply challenges. Examples of natural infrastructure include permeable paving, raingardens and constructed wetlands. These approaches can clean and filter water and provide additional benefits such as habitat, flood protection, cooler temperatures, recreational opportunities, and cleaner air.

We are creating a new model for urban conservation by using natural solutions to increase biodiversity, reconnect urban communities with nature and help secure Los Angeles’ water future. TNC is driving change in four major areas: policy, market solutions, science and on-the-ground projects.


We are working  to shift the current infrastructure paradigm so that natural infrastructure becomes the default choice over traditional gray infrastructure like channelized waterways. To do this, we are:

  • Pushing for local ballot measures to fund stormwater cleanup with provisions that include natural infrastructure solutions;
  •  Promoting the needed policy changes to facilitate the siting, implementation and maintenance of natural infrastructure; and
  • Advancing the science that demonstrates how natural infrastructure can provide biodiversity, climate resilience and other benefits to Californians.

Market Solutions

Though natural infrastructure ultimately saves money, it can be expensive to develop initially, so we need to help Los Angeles County create new ways to finance it. TNC is  working to leverage private capital to fund natural infrastructure construction and operations. Two tools, in particular, have demonstrated early promise:

  • Stormwater credit trading, which makes it easier and less costly for property owners to build high-impact natural infrastructure; and
  • Public-private partnerships, which reduce the cost of government-funded stormwater programs by contracting with private companies to implement a large portfolio of natural infrastructure projects.


River water bubbling over rocks.
L.A. River Habitat Assessment Close up of the Los Angeles River © © Steve and Julie (Creative Commons/Flickr)

Science and On-the-Ground Projects

TNC is developing the science to ensure that biodiversity is factored into decision making about investments in nature-based solutions.

By making nature an essential part of the equation, we can drive projects that protect and preserve the natural world while improving quality of life for urban residents.

L.A. River Habitat Assessment

The L.A. River is Los Angeles’ most visible stormwater infrastructure and the conduit for most of the stormwater runoff generated in the county. As we advance our Urban Conservation Program, we aim to use the L.A. River to prove that nature and infrastructure don’t have to be at odds—they can reinforce one another. In 2016, we completed a habitat assessment of a 2.5- mile soft-bottom portion of the river to evaluate potential projects. 

Over 12 months, we recorded:

  • More than 100 bird species
  • 17 mammal species, including coyotes and five different bat species; and
  •  7 reptile and amphibian species, including the western toad and Pacific chorus frog.

Our study established an ecological baseline for this stretch of the river, and this knowledge will allow us to understand how best to improve habitat, water supply, and water quality.

The L.A. River was channelized less than 100 years ago to address catastrophic flooding. Unfortunately, channelization has had unintended consequences, such as warming and creation of stormwater pollution, which we are still working to understand. TNC is working with partners to identify and implement opportunities for restoration and nature-based solutions along the river to improve the climate resiliency of the region. 

L.A. River Demonstration Projects 

TNC has supported prioritizing restoration projects along the L.A. River that enhance habitat, prevent housing displacement, provide public access to parks and open space, and promote climate resilience. We aspire to create a highly visible new model for urban restoration where habitat, water treatment, and public access combine in one place to demonstrate what the future of the L.A. River could be.

In partnership with California State Parks, TNC is developing a multi-benefit stormwater management and habitat enhancement project along the L.A. River in Northeast Los Angeles. The project will improve water quality, enhance habitat, and increase public access to the river. The project will be a model for urban restoration. 

Planting Stormwater Solutions

When it comes to nature-based solutions, where work is sited can be just as important as what the work entails. TNC recently developed a region-wide spatial analysis for Los Angeles to help prioritize locations for siting nature-based stormwater solutions. The team identified three main categories of benefits this work would seek to provide: biodiversity/habitat, public health, and water quality. We then chose indicators that allowed us to score different locations across the study area based on how effectively they could provide these benefits, and developed priority maps using geospatial analysis. The analysis can now be used to inform the siting and implementation of projects across the region.

Biodiversity Analysis in Los Angeles

TNC is collaborating with the Natural History Museum of Los Angeles to combine its world class community science programs with TNC’s expertise in planning to create a roadmap for deploying natural infrastructure in Los Angeles. Together, we launched Biodiversity Analysis in Los Angeles (BAILA), a first-of-its kind study that displays the surprising biodiversity of Los Angeles, even in its most developed neighborhoods. We hope that BAILA becomes a guide for planners and decision-makers by highlighting how infrastructure development has the potential to bring nature back to the city. We also hope it will guide individual project choices by showing developers how making strategic adjustments to their designs can benefit nature.

Another great example of a multi-benefit effort that will capture and clean storm water, enhance habitat, sequester carbon, and provide recreational space is the Bowtie Demonstration Project.  

Safeguarding Our Future

Now is the time to catalyze a new era of urban conservation. By addressing the need for new science, policy and funding frameworks in Los Angeles, TNC aims to create a scalable conservation model that can be applied in cities around the world.