Sustaining Claremont’s water system

by Mark von Wodtke, FASLA

How can Claremont sustain our water supply? Let’s see what 20/20 vision of our water system reveals.

Looking into the future, it is likely we will continue to see both severe drought and intense rains. It is likely that there could be less snow pack, which slows the release of water. Consequently, we need to find ways to capture more runoff to prevent both flooding and retain more water for our aquifer.

It is likely the cost of imported water will increase substantially to pay for added state water project infrastructure and address salt water intrusion that is likely to occur if sea level rises in the Sacramento River Delta. Consequently, Claremont needs to find ways to become more self-sufficient and import less water.

It is also likely that we will see the cost of this essential commodity be increased by water purveyors who control supplies. So, we need to seek local control of our potable water delivery system; or, working through the Public Utilities Commission, find ways to protect ourselves from for-profit water companies.

It is an injustice that private water purveyors may capitalize from a drought and benefit from the public’s investments in cleaning up and harvesting runoff. For-profit water companies are inherently conflicted when it comes to water conservation. Water purveyors should not be allowed to disrupt efforts to reclaim water for irrigation. Preparing for the 2020s, we need to clean and harvest water runoff. We could:

• Sustain and regenerate trees in our wilderness park and urban forest, which harvest rain and slow down runoff in our watershed.

• Address water percolation along the Thompson Creek Channel as proposed in the spreading ground study funded by a $200,000 grant from the Los Angeles and San Gabriel Rivers and Mountains Conservancy. Also create micro-catchments in the wilderness park (as was done in Sycamore Canyon Restoration Project.) Micro-catchments and spreading grounds would improve wildlife habitat, percolate more water into the aquifer under Claremont, reduce sediment deposits behind the dam in Thompson Creek, and reduce the risks of flooding along the channel due to the likelihood of more intense storms in our foothills. Hopefully the Claremont Wilderness Area Preservation Plan will help address this.

• Build upon the city’s MS4 Program to clean up urban runoff. The city is currently paying more than $800,000 per year for the mandated monitoring of runoff. We need to move beyond monitoring and clean up and reduce runoff from our streets.

• Add keylines capturing runoff along the contours of the alluvial fan we live on. (See “Keys to Making Claremont an Even Better Place to Live,” a Sustainable Claremont Tree Action Group (TAG) handout showing how to integrate water harvesting on the alluvial fan of Claremont. This article was also published in the Claremont COURIER more than a year ago.)

• Build bioswales as part of the Foothill Boulevard Renovation Plan. This could be the first phase of the MS4 Program as proposed in the city staff report by Brian Desatnik. Including walkways and bike paths with permeable pavement and no curbs can capture more water in the soil to help sustain significant street trees, shading the walkways and bike paths. Foothill Boulevard could serve as a prototype for more keylines along Base Line Road, Arrow Highway and San Jose Avenue.

• Add more water retention basins like those already integrated into the Claremont Business Park and Meadowood development. These could be integrated into development of the Vortox and Hibbard properties along Indian Hill Blvd. as well as the golf course property next to Rancho Santa Ana Botanic Garden.

• Encourage more residential rainwater harvesting to capture runoff on each property, resulting in zero runoff. This can include rain barrels for roof runoff, drywells in paved areas as well as landscape swales and ponds. (The von Wodtke and Herbold residences, which have zero-runoff, provide examples of what can be done here in Claremont.) See also the TreePeople “Save the Drop” program. TreePeople also led a study of best water-conservation practices for the LA Flood Control District.

In the 2020s we could be reclaiming waste water. Having control of the water company would make this easier to do because a private water company, seeking to control our water supply, is likely to oppose these proposals. We could:

• Install a package wastewater treatment plant to provide irrigation for the Claremont Colleges. See the study commissioned by the Claremont University Consortium entitled “Recycled Water Feasibility and Engineering Study The Claremont Colleges.”  

• Add more package treatment plants to provide irrigation for city parks and street trees. Reclaiming water to use for irrigation might reduce water demand by 30 percent, making it more possible to sustain Claremont with potable water pumped from local wells.

• Pump high-nitrate wells and use the water to irrigate trees in our urban forest and urban food production while, at the same time, cleaning chemicals (such as nitrates) from the aquifer and reviving the contaminated wells.

• Reclaim water used to flush Claremont’s potable water system and fire hydrants and make use of this water to irrigate trees instead of sending the water down storm drains. Use mobile watering capabilities (such as a tank-on-a-trailer) filled up at hydrants on any street to re-use for supplemental watering of street trees, especially where necessary to sustain heritage trees during times of drought and help establish new trees. 

• Incentivize greywater systems now permitted under the new building code. Claremont could provide incentives (much like the current turf reduction incentive) for homeowners to install properly-designed greywater reuse systems to water trees on private property. (See

• Renovate city parks and private landscapes to provide compost beds that both capture and filter storm water. This would help the community reduce irrigation needs as well as the need to cart off green waste—instead using it to help sustain our green infrastructure.

Working together as a community, Claremont could sustain its water supply into the 2020s and beyond. As part of humanity we need to support the Paris Climate Accord and work to help stabilize the climate.

As a local community, we need to go beyond water conservation and carry out policies and actions that will improve our public infrastructure to clean up and harvest runoff, as well as reclaim water. Our water comes not from a water purveyor, but from natural processes. We need to learn to more-effectively manage these processes for the common good, especially when faced with a changing climate.


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