The quality and quantity of water flowing through our creeks, and ultimately into our estuaries, are critical to both ecological health and human use. Within the Santa Maria River watershed, perennial creeks are limited. Those that do exist are often highly modified, lacking native vegetation and influenced by agricultural runoff that carries elevated salt and nutrient loads.

To better understand these systems and how to protect them, Coastal San Luis Resource Conservation District has partnered with local landowners, California State Parks, and the Regional Water Quality Control Board to implement a comprehensive monitoring program in Oso Flaco and Orcutt Creeks, the two primary perennial waterways in the lower watershed.

Monitoring Approach

This program focuses on answering a key water management question: How much water and salt are leaving the basin through perennial streamflow?

To address this, CSLRCD has installed and maintains continuous acoustic Doppler flow meters in each creek. These instruments measure water velocity and depth in real time, allowing for accurate calculation of streamflow. In addition to continuous monitoring, staff conduct regular manual flow measurements and collect monthly water samples to analyze for salinity and related constituents.

Because these creeks are largely fed by shallow groundwater, tracking both flow and salt concentrations is essential for understanding how salts move through the landscape and exit the basin.

Equipment and Data Collection

The monitoring system uses advanced technology, including the SonTek IQ flow meter, which captures three-dimensional water velocity using multiple acoustic beams. Installed at the deepest part of the channel, the device provides a detailed and continuous picture of flow conditions.

Supporting infrastructure includes a small bank-mounted enclosure for data logging equipment and safe access features, such as a simple crossing structure, to allow staff to conduct maintenance and field measurements.

 

Why This Matters

By pairing continuous flow monitoring with water quality sampling, this program allows for detailed analysis of salt loading in the lower watershed. These insights are critical for:

• Understanding watershed-scale water and salt balance
• Informing agricultural and land management practices
• Supporting regulatory and conservation efforts
• Protecting downstream habitats and estuarine ecosystems

Over time, this data-driven approach will help guide more effective strategies to reduce pollutant impacts and improve overall watershed health.

 

Partners: State Parks, RWQCB
Funders: Private
RCD Contact: Samantha Alvarez, salvarez@coastalrcd.org