Anonymous
Rain brings good news for local reservoirs: shown here is Jameson Lake on 1-17-19. Thursday morning’s rain event increased the lake’s elevation by more than 6 feet in less than 6 hours. Current elevation is approximately 7 feet below capacity. While water typically looks murky during a rain event, in this photo charred brush and water quality impacts from the Thomas Fire are evident. (Photo Credit: Alan Prichard)
Source: Montecito Water District
While residents have had to brave evacuations and rainy weather on the heels of the anniversary of last year’s January 9, 2018 Thomas Fire Debris Flow incident, this week’s storms carried needed rain for the community of Montecito. Thursday’s storm brought precipitation over the Santa Ynez River upper watershed and seemingly concentrated over Jameson Lake, a key resource for the Montecito Water District. As of mid-day January 17, 2019, the County’s rain gauge located at Jameson Lake recorded 6.19 inches of rainfall for the prior 24-hour period, which is approximately five inches greater than rainfall measured during the same time period in Montecito at the District’s office.
The current capacity of the lake is approximately 5,144 acre-feet with a storage elevation of 2,224 feet. Thursday’s event put the lake at 2217 feet and rising, which leaves an estimated 7 feet of elevation before it reaches capacity. The series of winter storms which began on Sunday, January 13th and is forecasted to end today, January 17th, brought an estimated 1,250 acre feet of runoff to Jameson Lake increasing the total storage to approximately 4,300 AF or 83% of full.
Even when the rain stops, runoff and surrounding streams should keep the lake level rising. This combined with any future rain events could cause Jameson Lake to “spill.” Spill water flows downstream via the Santa Ynez River towards Gibraltar reservoir, and spill from Gibraltar continues in the direction of Lake Cachuma.
While this is great news for water supply, it remains to be determined what impact this inflow will have on water quality. Since the Thomas Fire burned through the watershed in December 2017, each rain event deposits more ash and debris in the lake. Increased contaminants make treatment difficult and as a result, water deliveries from Jameson Lake have been suspended since the Thomas Fire.
The District is completing a treatment improvement project at its primary water treatment facility with the intent of enhancing its ability to treat this supply. It is unlikely that inflow from the recent storms has improved water quality, and water deliveries from Jameson Lake are likely to remain suspended over the coming months until water quality improves or the treatment enhancements prove to be successful. The District will continue to monitor both quantity and quality around the clock and reports that there are no storm-related issues with water service at this time.
Per Rain.cosbpw.net there’s been about a 6’ rise in Lake Cachuma with the recent storms.
Which puts it’s current capacity at 36.1 %.