Marin Water has given the public an additional two months to weigh in on its controversial plan to raise the Nicasio Reservoir spillway, a move some fear would flood several residences along with the school grounds. The project is one of several being considered to increase the district’s storage capacity to cope with future drought. Members of the Nicasio Land Owners Association believe Marin Water is underestimating the potential impacts. The district will now take public comment through Aug. 15 as it determines the scope of an environmental impact report assessing the $15 million project. It has also scheduled a third virtual public meeting, on July 15. The project would involve installing a 280-foot-long, 4.4-foot-high inflatable rubber gate spanning the top of the spillway. The gate would be inflated during the wet season to increase storage in the reservoir, which is fed by Halleck and Nicasio Creeks. It would be lowered during the dry season. The heightened spillway would increase the reservoir’s capacity by 3,700 acre-feet, an increase of roughly 15 percent. (An acre-foot is about 326,000 gallons, or enough water to cover an acre of land about 1 foot deep.) Construction would begin in 2027. Marin Water owns much of the land around the reservoir where the waters would rise, but inundation maps show the flooding would extend beyond its own property lines. Thomas Wood, who has lived in town for 50 years, said Nicasio Creek already rises by 8 feet several times a year during the rainy season. “Even in the non-winter months, raising the spillway will impact low-lying areas, especially the Nicasio School, which is the main focus of our concerns,” Mr. Wood said. “They have yards and fields, and this is going to be just devastating. There’s going to be a lake in there. I don’t know what they are thinking.” The district holds its first public scoping meeting on May 22. The remaining sessions take place from 1 to 3 p.m. on May 27 and July 15 on Zoom. Find information in our calendar and at https://www.marinwater.org/node/1261