Integrated Water Management at the Peri-Urban Interface: A Case Study of Monterey, California

Abstract

Climate change, drought, and chronic overdraft represent growing threats to the sustainability of water supplies in dry environments. The Monterey/Salinas region in California exemplifies a new era of integrated or “one water” management that is using all of the water it can get to achieve more sustainable supplies to benefit cities, agriculture, and the environment. This program is the first of its kind to reuse a variety of waters including wastewater, stormwater, food industry processing water, and agricultural drainage water. This study investigates the partnerships, projects, and innovations that shape Monterey’s integrated water network in order to better understand the challenges and opportunities facing California communities as they seek to sustainably manage peri-urban water supplies. Water reuse in the Monterey region produces substantial economic and environmental benefits, from tourism and irrigation of high-value crops to protection of groundwater and increases in environmental flows and water quality. Water resource managers in other communities can learn from Monterey’s success leveraging local needs and regional partnerships to develop effective integrated water solutions. However, key challenges remain in resolving mismatched timing between water availability and demand, funding alternative water supplies, and planning effectively under uncertainty. Opportunities exist to increase Monterey’s recycled water supply by up to 50%, but this requires investment in seasonal storage and depends on whether desalination or additional recycling forms the next chapter in the region’s water supply story. Regulatory guidance is needed on seasonal subsurface storage of tertiary-treated recycled water as distinct from potable recharge. By increasing the supply of recycled water to Monterey’s indirect potable use system, the region’s potential need for seawater desalination may be delayed as much as 30 years, resulting in cost and energy savings, and giving the opportunity to resolve present planning concerns.