Local organizations have issued a report about their work to improve community lakes, in particular Laguna Joaquin. The Rancho Murieta Association, Community Services District and downstream ranchers are represented in the group, which was formed in response to last July's fish kill at Laguna Joaquin.
The group plans a series of community meetings about its work. Here is its report, released through the RMA:
IMPROVING RANCHO MURIETA WATERS
Over the years ongoing concerns about the condition of several lakes in Rancho Murieta have been repeatedly discussed based on varying water-quality and aesthetic issues. Of specific interest in the North is Laguna Joaquin near the entrance and Guadalupe Reservoir, and in the South, Basin 5 (Lost Lake).
In July of 2017, low water levels and unusually warm stagnant water in Laguna Joaquin led to a significant algal bloom. The algae growth resulted in clogging the pumps that are used for irrigating the common area. Attempting to control the algal bloom resulted in a large and unexpected fish kill. As a result, the community realized that it was critical to find a long-term solution to improve the health of Laguna Joaquin and other community lakes.
The water in Laguna Joaquin comes from rainfall and irrigation runoff, as well as water diverted from the Cosumnes River. After July 1st RMA has only limited access to Cosumnes River diversions. Re-charge of Laguna Joaquin is limited to RMA’s irrigation rights and water that may be routed through it to the Anderson Ranch and Equestrian center. Competing water demands and seasonal Cosumnes River flows supplying the CIA ditch which adds water to the Lake in summer months make filling or lowering the Lake difficult at times. The water is used not only by RMA for irrigation but also may be used by the downstream Ranch.
In the spring of 2017 special aerating pumps were installed in Laguna Joaquin to increase the oxygen levels which will aid in improving the overall water quality of the lake. During the late summer, some water was removed from the lake, as well as sediment accumulation, garbage, and select water plants. The lake was then refilled with fresh water and catfish were restocked. In mid-spring 2018, bass and bluegill will also be added. These fish are known to aid in controlling the midge flies by eating their larvae.
A Lakes group that included representatives from RMA, the RMCSD, a downstream Ranch representative, and a local resident was formed. The sole purpose of this group was to investigate possible solutions to improve the health of all community waters, with focus being on Laguna Joaquin due to poor water quality and its multiple uses. The goals for Laguna Joaquin are to improve the water used by RMA for irrigation, be of reasonable quality for Ranch use, healthier for fish, and to become more aesthetically pleasing.
This Lakes group consulted environmental experts at California State University at Sacramento (CSUS), California Fish and Game, and local specialists, which included a biologist, geologist, environmentalist, engineer, and local managers. One significant recommendation was to utilize natural vegetation to catch, filter, slow down run-off, and provide nutrient uptake of drainage waters. This process is currently used in the upper lakes of RM North. Past practices at Laguna Joaquin have been to kill off vegetation that would perform this essential work to create a more manicured look.
RMA and RMCSD are planning to initiate four steps to improve the health of Laguna Joaquin. First, a light dye will be applied. This will give the lake a more pleasing appearance, but more importantly, restrict sunlight penetration into the lake. Less sunlight penetration will result in cooler water and less algal growth. Second, the lake will receive routine cleaning and surface skimming and natural aquatic plants will be allowed to grow in the inlet areas of the lake. These plants play a significant role in cleaning the water and reducing the need for herbicides. Third, the RMCSD and RMA will reduce their use of pesticides and herbicides and encourage residents and golf course managers to do the same. Fourth, we are investigating the ability to control the nutrients entering our lakes through runoff by constructing ‘bio-retention swales’ (rain gardens) in the inflow channels. These swales are small depressions filled with specific natural vegetation designed to trap sediment and consume the nutrient load before it enters the lake. Other ideas, 1. Reduce the amount of grass being irrigated by adding ‘xeroscapes’. 2. Seek additional sources for irrigation water to reduce the impact on Laguna Joaquin. 3. Installing a more efficient irrigation system. 4. Continue public outreach.
A series of Town Hall meetings is planned to answer questions from the public.