Denniston Creek is a U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data
The National Map
, accessed March 15, 2011 coastal stream in western

San Mateo County, California San Mateo County ( ), officially the County of San Mateo, is a county located in the U.S. state of California. As of the 2020 census, the population was 764,442. Redwood City is the county seat, and the third most populated city following Dal ...

. Denniston Creek rises on the western slopes of

Montara Mountain Montara Mountain, positioned between the unincorporated community of Montara, California, to the southwest and the city of Pacifica, California, to the north, forms the northern spur of the Santa Cruz Mountains, a narrow mountain range running the ...

and discharges to the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

at Pillar Point Harbor somewhat north of El Granada Beach. The watershed of Denniston Creek is made up of relatively permeable sandy soils capable of significant recharge to its aquifers, which supply a moderate amount of potable water to the local area.

Groundwater

In the

headwaters The headwaters of a river or stream is the farthest place in that river or stream from its estuary or downstream confluence with another river, as measured along the course of the river. It is also known as a river's source. Definition The ...

reach high on Montara Mountain, coarse grained

decomposed granite Decomposed granite is a kind of granite rock that is weathered to the point that the parent material readily fractures into smaller pieces of weaker rock. Further weathering yields material that easily crumbles into mixtures of gravel-sized par ...

overlies heavily fractured

granitic A granitoid is a generic term for a diverse category of coarse-grained igneous rocks that consist predominantly of quartz, plagioclase, and alkali feldspar. Granitoids range from plagioclase-rich tonalites to alkali-rich syenites and from quartz- ...

based bedrock

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials ( gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characteris ...

s. This upper pocket

groundwater Groundwater is the water present beneath Earth's surface in rock and soil pore spaces and in the fractures of rock formations. About 30 percent of all readily available freshwater in the world is groundwater. A unit of rock or an unconsolidated ...

complex feeds down-basin

alluvial Alluvium (from Latin ''alluvius'', from ''alluere'' 'to wash against') is loose clay, silt, sand, or gravel that has been deposited by running water in a stream bed, on a floodplain, in an alluvial fan or beach, or in similar settings. All ...

fan deposits on the

coastal plain A coastal plain is flat, low-lying land adjacent to a sea coast. A fall line commonly marks the border between a coastal plain and a piedmont area. Some of the largest coastal plains are in Alaska and the southeastern United States. The Gulf Co ...

. These alluvial fans exhibit some characteristics of a confined aquifer, but also respond to pressure and recharge from

precipitation In meteorology, precipitation is any product of the condensation of atmospheric water vapor that falls under gravitational pull from clouds. The main forms of precipitation include drizzle, rain, sleet, snow, ice pellets, graupel and hail. ...

Mouth

At the mouth of Denniston Creek, the stream cuts through a gently sloping marine terrace plain of alluvium. In a 1980s biological survey, sightings of the

endangered An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and in ...

San Francisco garter snake The San Francisco garter snake (''Thamnophis sirtalis tetrataenia'') is a slender multi-colored subspecies of the common garter snake. Designated as an endangered subspecies since the year 1967, it is endemic to San Mateo County and the extrem ...

were made. Denniston Creek is within the domain of the San Mateo County Local Coastal Plan

References

Rivers of San Mateo County, California Rivers of Northern California {{California-river-stub

Groundwater

Mouth

See also

References