Friday, May 10, 2013

Sustainable Water Use in the Ventura River Watershed


On April 23, 2013 the Ventura River Watershed Council received a presentation from the UCSB/Bren School team on the results of their year-long Masters project titled 'Sustainable Water Use in the Ventura River Watershed.'

Bren project website http://www2.bren.ucsb.edu/~venturariver/

The project objectives are:


  1. Create a comprehensive watershed model
  2. Evaluate the effects of climate change and land use change on the water budget
  3. Identify actionable water resource management projects
  4. Propose a set of recommendations relevant to securing Proposition 84 funding, increasing water availability, and improving ecosystem function

The team based its analysis on a comprehensive water supply and demand model utilizing local data and the established WEAP software.  The model provides the opportunity to assess water management scenarios watershed-wide.  Development of this model was no small task given the complexity of our system with its multiple jurisdictions, water districts, and water users. Two graduate students worked as interns over the summer to compile data and 'connect the dots' between supply and demand throughout the watershed.  


Description of the Ventura River WEAP model

Once all the data was input, the model was validated by comparing modeled and measured stream flows and reservoir levels over the planning period.  From this a general water budget could be estimated. (note that this was based on the 'average' over the 1990-2009 planning period)

Water Budget from the Ventura River WEAP model

 Water management strategies were evaluated based on six criteria: ability to decrease demand, ability to increase supply, cost-effectiveness, benefits to ecosystem health, benefits to water quality, and suitability for Proposition 84 funding.  Results from the analysis suggest that, while climate and land use change have the potential to severely impact water availability within the watershed, implementing water resource management strategies can offset the impacts. 



Results for the Ocean Friendly Gardens scenario from the Ventura River WEAP model

Conclusions:

Consumer-based strategies such as ocean friendly gardens and greywater systems in single family homes were shown to be very cost-effective options for reducing water demand and increasing water supply, benefiting riparian ecosystem health. Although they are less cost-effective than consumer-based strategies, infrastructure-based solutions such as decentralized infiltration basins were shown to be viable pathways towards increasing water supplies and improving water quality. Results further suggest that the most effective option for decreasing demand within the watershed is by increasing water rates, thereby incentivizing conservation.







Recommendations:

  • Encourage widespread adoption of ocean friendly gardens and greywater systems
  • Implement a program to install a decentralized infiltration basins to capture stormwater runoff
  • Increase lowest water rates in the watershed to the state average




Two workshops have been scheduled (May 16 and May 23) to train watershed council members so that this model can continue to be developed and used in watershed planning efforts.  For more info contact Bill O'Brien: billo@ngeneng.com



References:
Bren Project:

On this blog:  http://www.venturariver.org/2012/05/ucsb-bren-school-project.html