[Dec 6]
Strategies For Improving Water Security For The Navarro Community
by Linda MacElwee & Patty Madigan
As a relatively dry fall gives way to winter, local residents are hoping for a good rain year while still worried that it will be another dry year and possibly the start of another drought. The alarming trajectory we’ve seen in recent years of low rainfall in the Navarro and throughout northern California threaten the security of our water supply as well as the health of our rivers and fisheries. Climate change is making the situation worse with predicted increases in the frequency and intensity of drought periods. While we hope the Farmer’s Almanac’s prediction of a cold and wet winter holds true, we know it is just a matter of time before the next year when the rains fall short and we’re eventually faced with another drought.
To safeguard the health and well-being of the Navarro watershed now and into the future, the Mendocino County Resource Conservation District is stepping up its efforts to work with the community to implement projects and strategies to improve water supply security that also benefit the health of our rivers and fish. To turn the tide of increasing vulnerability and diminishing stream flows, we are enlisting the help of landowners, farmers and vineyards and leveraging partnerships with the Nature Conservancy (TNC), Trout Unlimited (TU), Natural Resources Conservation Service, University of California Cooperative Extension and Shippensburg University. But success will depend on broad support and active participation of the Navarro watershed community. On December 6th, we’re kicking-off our community outreach effort by hosting an event at the Grange in Philo from 6-9 to share useful information and water management strategies and to encourage local participation.
We’ve been hard at work on this problem already. Over the past 3 years, the MCRCD and our project partners The Nature Conservancy and Trout Unlimited have worked with a nearly a dozen landowners to gather data, implement projects and develop win-win strategies that work for people and fish. Low summer flows, especially in drought years can impact homes and businesses that rely on diversions from streams. In the recent drought, some stream reaches dried up and landowners were forced to truck in water. Extreme low flows are also hard on our endangered salmon and steelhead populations. The late summer and fall is when the young of the year salmon and steelhead need stream reaches to stay wet and maintain pools that stay cool enough for them to survive until the winter rains come. It also happens to be when people and our farms, gardens, and enterprises most need water and when the least amount of water is available. With funding from the Wildlife Conservation Board, this past summer we completed initial planning and project development where we reviewed existing salmon and steelhead recovery and restoration plans to identify projects and management actions to enhance flows and build drought resilience in the watershed. Our partners TNC and TU collected streamflow data throughout the watershed and developed an assessment of estimated water need in the Navarro watershed. We also created a decision-support tool to help identify areas in the watershed where water management projects will most quickly assist in the recovery of coho salmon and steelhead and therefore be more likely to access fisheries restoration funding.
The good news is that we have enough water. The total estimated amount of water needed each year for all users in the Navarro watershed is about 1800 acre-feet - less than 1% of the average annual runoff of about 240,000 acre-feet. But about 80% of all water use is in the driest months of the year when instream flows and water supplies are at their lowest. The solution to the Navarro’s water supply problems seem obvious – reduce reliance on dry season diversions by storing the wet season rainfall for use during the dry season. But implementing water management projects can be difficult. Issues related to permitting, water rights, flow requirements, project design and cost have kept many water users from taking steps to improve their water security. The MCRCD and its partners are focused on strategies to overcome these challenges and empowering water users to implement solutions and management strategies to meet the needs of people and fish. We have two main strategies.
Our first strategy is to store wet season water for use in drier months and reduce the cumulative impacts of dry season diversions. While rainwater capture systems, ponds and tank storage are not new to the Navarro watershed, they are, often difficult to permit and underutilized. The Mendocino County Resource Conservation District and our conservation partners TNC and TU recently received a second grant from the Wildlife Conservation Board to continue our work to promote and demonstrate a variety of storage and flow enhancement projects. Over the next two years we will install two new storage projects and develop designs for four more. We will also pilot a new landowner-based Collaborative Water Management project in a tributary to the Navarro to improving water supply reliability and instream flows at a watershed scale. Working with willing landowners, we’ll identify water management projects that meet their needs and create a plan which will facilitate permitting and future funding to support a more resilient watershed and community. We’ll also pilot a project to coordinate timing of diversions. By working together, water users can reduce the impacts of existing diversions simply by coordinating when and how much water is diverted at one time. Much like people filling an elevator, if everyone tries to enter at the same time there is not enough room, but by taking turns there is room for everyone.
Our second strategy is to increase storage of water naturally - in the ground. Shallow groundwater drains out slowly into our streams over the dry season and enhances streamflows, naturally maintaining flows for juvenile salmon and steelhead. But changes in land management and have decreased the natural infiltration of rainfall into the ground that forms groundwater storage. The first step to improve this situation and increase groundwater storage is to slow runoff when the rains fall, giving the water time to sink into the soil (infiltrate) and recharge groundwater supplies. Increasing soil organic matter in the soil increases the water holding capacity and sequesters carbon, two strategies we need more of across the entire planet. Increasing soil organic matter by 1% is estimated to hold as much as 20,000 gallons of water in the soil allowing it to sink in slowly and recharge groundwater supplies. Similarly, more water in our streams can be stored in the adjacent hillsides by slowing run-off using structures made of fallen trees. Increasing the amount of large wood and trees in streams creates pools for fish, but also raises the groundwater table and stores water that will release to the stream later in the dry season when the needs are greatest.
Over the next two years we’ll be advancing our groundwater and soil health strategy in two ways. As part of our “Navarro Farm to Water Table” project we will be collaborating with our partners at Natural Resource Conservation Service and Professor Christopher Woltemade of Shippensburg University to work with farmers and ranchers to implement conservation practices that build soil health, sequester carbon, increase water holding capacity, and water-use efficiencies such as replacing failing or leaking irrigation systems and conveyance. To support this work, we’ll be engaging local volunteers in a citizen monitoring program where landowners will participate in gathering temperature data throughout the watershed. Together with TNC and TU we’ll also be designing and constructing large wood restoration projects in several watersheds. We’ll also be implementing an infiltration study to better quantify the benefits of shallow groundwater storage to enhancing streamflow.
For both people and fish, now is the time to begin thinking like a watershed, do our part, however small or large, to return the Navarro to a healthy, productive river ecosystem.
If you are interested to learn more about all of these activities and strategies, please join us for a Community Meeting, The Future of the Navarro River Watershed: Stream Flows and Water Security Strategies for Farms, People and Fish on December 6th at the Anderson Valley Grange from 6-9 pm. We will begin with a potluck supper from 6-7, and presentations beginning promptly at 7:00 pm. For more information you can email or phone Linda.macelwee@mcrcd.org (707)895-3230, patty.madigan@mcrcd.org (707) 462-3664 ext. 102, or go to www.mcrcd.org.
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