The ongoing drought in California has the California Department of Transportation (Caltrans) investing in infrastructure — new and upgrades — to help conserve water in the immediate and for the future.
Caltrans District 11 — San Diego and Imperial County will be investing millions of dollars on projects and initiatives to conserve water, which translates into more work for general contractors and more efficient systems.
“We recognize our responsibility to lead by example as drought conditions continue throughout the state,” said Edward Cartagena, Caltrans media information officer, “and are doing more than ever before to continue a consistent, downward trend in water usage along its state highway landscaping and to exceed state and local mandated requirements.
Caltrans used approximately 1.07 billion gal. for the roadside landscape in 2014.
“There was an approximate 25 percent savings from the 2013 usage that exceeds the governor’s 20 percent goal defined in the January 2014 emergency proclamation,” said Cartagena. “The department is setting a statewide goal for an additional 25 percent as the drought continues. The peak demand for roadside watering occurs between August and September.”
Irrigation for the roadside is irrigated with sprinklers and pipe delivery systems.
“Currently there is about 119 highway centerline miles that are irrigated with potable water and approximately 66 highway centerline miles irrigated with recycled water,” said Cartagena. “Water is distributed to the roadside landscape efficiently and is used by the roadside vegetation, there is no excess run-off. Caltrans does not treat or deliver water — this is done by the water purveyors. Caltrans is an end-user that carefully uses its allocated water resources.”
The investment in new infrastructure by Caltrans on water infrastructure is considerable, with District 11 investing $3.4 million in “smart controller” upgrades.
“The goal is to have 100 percent smart controller capability in the next several years for all the viable irrigated landscapes in the district,” said Cartagena. “Smart controllers allow greater management of our water resources by giving maintenance the ability to manage the system remotely, use weather data to set schedules (including turning off the system during rain events) and use flow sensing that turns off water as a result of broken pipes or sprinklers.
“District 11 is also expanding their recycled water infrastructure,” he added. “Currently the district has a $2.07 million project to expand the recycled water lines from state Route 52 to I-805 and in the south bay to expand the recycled water system at the I-805/905 interchange. We are also seeking funds to expand at I-805/I-5 merge in Sorrento Valley, the western portion of state Route 56 to I-5 and further expansion of recycled water on I-805 in the south bay.”
Replacement is a must for parts of the irrigation system, with some elements being more than 40 years old.
“As a result of freeway widening and highway projects,” said Cartagena, “the systems that are impacted are modernized and upgraded. In addition projects such as upgrading of our control systems to smart controller technology also include the opportunity to evaluate the irrigation delivery systems to make needed repairs, abandon system that are no longer needed, and retrofit to more efficient delivery solutions.
“The department has set a 50 percent reduction state-wide during this period of unprecedented drought,” he added. “District 11 has set a long term goal to convert 75 percent of the roadside landscape to solutions that require no supplemental irrigation once established, as well as using recycled water or non-potable sources whenever possible when irrigation is utilized.”
Most of rain collection by District 11 has occurred via the result of storm water efforts.
“Best management practices (BMP’s) such a bio-filtration swales, detention basins, retention basins, and structural subsurface retention systems have been a benefit to the roadside landscape by recharging water tables,” said Cartagena, “and adding to the surface water retention in vegetated areas [is helping], as well as keeping our waterways clean. Several projects have also altered grading to capture onsite rain water in an effort of water harvesting for the roadside landscape.”
In the District 11 region, Caltrans is responsible for maintaining nearly 4,000 acres of highway landscaping and while the landscaped areas provide pleasant visuals, they have a greater purpose — serving as fire brakes, preventing erosion, and acting as visual and noise barriers for adjacent residential neighborhoods.
While part of the plan is to expand the planting of native and drought-tolerant plants to reduce long-term water usage and maintenance, as well using mulch and rockscape options, installing “smart” irrigation systems to optimize water usage and the use of recycled water is critical.
“We took notable steps taken in recent years to reduce highway landscape water use in the region, and more options are being explored as restrictions tighten,” said Cartagena. “These measures included upgrading irrigation controllers that are operated through a computer-based Central Control System, which has high-flow detection to identify breaks and responds with an automatic turn off; the collection of data to measure how much moisture is lost from a plant based on weather conditions; and automatic shut-down of the irrigation schedule during rainy weather.
“Irrigation controllers not on central control still need to be manually turned off by maintenance crews or contractors,” he added. “Working with maintenance forces and construction contractors has allowed us to improve irrigation practices and repair irrigation breaks to minimize water loss. We also stopped irrigation of turf grasses and lawns at roadside rest areas, highway maintenance yards and truck inspection facilities.”
Other initiatives saw the installation of programmed controllers to reduce irrigation and nighttime irrigation and the use of placed mulch to reduce landscape water loss due to evaporation.
Contractors were brought in to replace/upgrade irrigation controllers to “smart” technology and replace inefficient sprinkler heads and ineffective automatic remote control valves, and highway maintenance station and roadside rest area faucets, urinals and toilets with more efficient, low water-flow systems.
Caltrans uses recycled water in areas where it is supplied to it and it continues to work with suppliers to expand the network of recycled water lines. This is translating into new projects that are being planned, such as the installation of lines to large segments of Interstate 5 (I-5) and the North Coast and state Route 56.
“There are also plans is to expand recycled water use in the southern part of the county as projects develop on I-5, Interstate 805 and state Route 905,” said Cartagena.
Environmental concerns and regulations also require Caltrans and its partners and stakeholders to create wetlands and other habitats as environmental mitigation for the construction of transportation projects.
“These sites often require irrigation to establish habitats for wildlife and flora,” said Cartagena. “To do this, we and the permitting agencies negotiate the required level of mitigation in accordance with the California Environmental Quality Act, National Environmental Policy Act, the Clean Water Act, the Endangered Species Act and the California Coastal Act.
“The basic thought is that when Caltrans builds a project and if that project creates impacts,” he added, “the department complies with its commitments to mitigate those impacts. Sometimes the mitigation may create impacts of its own, such as irrigation, and the department balances this need with water reductions in other areas.”
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