Center gets grant for study of San Gregorio Creek
Their grassroots operation got a big boost earlier this month when the state Water Resources Control Board awarded the San Gregorio Environmental Center a $500,000 grant to do a complete assessment to determine what ails the watershed and propose a plan to heal it. The problems the group began noticing several years ago — below-normal water flow in the summer months, sediment buildup that alters the way channels flow — also plague several other watersheds in the area, including nearby Pescadero's. But without money to study the situation properly, it would be impossible to determine whether the causes are natural or man-made, said Neil Panton, executive director of the San Gregorio Environmental Center. The grant will pair local volunteers with scientists from the U.S. Geological Survey and Notre Dame de Namur University. It is designed to "pick up the slack" from government agencies such as the California Department of Fish and Game, which don't have the manpower to collect week-to-week data on the creek, said Panton. "It's really something the watershed has needed for a long time. Without these comprehensive assessments,you're not saying anything scientific about it," he said. In non-scientific terms, the problem is that sediment chokes up the stream bed, which reduces water flow. Low water flow, in turn, changes water quality and temperature, leaving fish and other species with less habitat. The samples Panton's group has collected from different points in San Gregorio Creek confirmed that two to three years ago, the sediment levels began to increase dramatically. They worried that a corresponding increase in temperature could be causing the creek's steelhead trout population to suffer, which has happened in Pescadero Creek. "We couldn't directly say that we saw fish populations drop ... but you know that these things contribute to making it difficult for many species to survive," said Panton. Another fish species, the coho salmon, has disappeared from the watershed completely. Panton has several theories about how some of these changes came about. One of them dates back to 1955, when the road running through San Gregorio was realigned through several tall hillsides in order to straighten it out. The steep slopes that were created still slide into the road in the rainy season, said Panton. "Then the road crews sweep it off the side of the road, and it goes right into the creek." Jim Steele, a former biologist with the Department of Fish and Game who spent years observing streams along the San Mateo County coast, said the problem is due at least in part to a 40-year housing boom in the area. "There's sedimentation in all the streams along the coast. Whenever you get a road next to the stream, and there are plenty, you get sediment in there," said Steele. "There have been people moving in there upstream. Any time that happens, wells are installed and the water level drops," he added. One theory about the disappearance of the coho holds that layers of sediment filled up the deep, cool pools the fish rely on to spawn, said Steele. The problems in San Gregorio Creek could imperil two other threatened species, as well: the California red-legged frog, which likes streams with large pools, and the San Francisco garter snake, which relies on wetlands, he added. The declining water levels also could be explained by natural factors such as climate change, with a naturally dry period following a wet one, said Steele. Likewise, rainfall naturally raises water levels and erodes stream banks. Once they determine the causes and extent of the problem, Panton's team will have until 2008 to formulate some solutions, which could include removing logjam barriers and stabilizing creek banks with trees and other forms of natural engineering. Staff writer Julia Scott covers the coast and the environment. She can be reached at 348-4340 or at jscott@sanmateocountytimes.com. |
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