Arroyo de en Medio (Spanish for "in the middle creek") is a 2.5-mile-long (4.0 km)[1] coastal stream in western San Mateo County, California. Arroyo de en Medio rises on the western slopes of Montara Mountain and discharges to the Pacific Ocean at Half Moon Bay at the location of the unincorporated community of Miramar at Miramar Beach. The watershed of Arroyo de en Medio consists of relatively permeable sandy soils capable of significant recharge to its aquifers, which supply considerable potable water to the local area. Arroyo is Spanish for creek; de en Medio means literally "of in between" but a closer more functional translation may be in the middle.
Mouth of Arroyo de en Medio, where it enters the Pacific Ocean
In the headwaters area, coarse grained decomposed granite overlies heavily fractured granitic based bedrockaquifers.[2] This upper pocket groundwater complex feeds down-basin alluvial fan deposits on the coastal plain. These alluvial fans exhibit some characteristics of a confined aquifer, but also respond to recharge from precipitation.[3]
Mouthedit
At the mouth of Arroyo de en Medio, the stream cuts through a flat marine terrace plain of alluvium, forming steep sided banks of approximately 40 degrees with respect to the channel floor; the channel floor is about eight meters deep relative to the bank tops. Even at the mouth, Arroyo de en Medio is considered intermittent, since the flow typically ceases in the summer months. However, there is some summer standing water in the channel near the mouth, the result of street runoff from summer irrigation and car washing. The stream mouth is clear of canopy vegetation but densely filled with sedges in a marshy setting.
Vegetation at the mouth of Arroyo de en Medio
The streambed at the mouth is essentially covered by water dependent plant species. These include willow (Salix sp.), sedge (Carex sp.), stream monkey flower (Mimulus sp.) and red alder (Alnus oregona).[4] These and other riparian plants form the food resource of many faunal species, either directly or indirectly. Many orb web weaving spiders at the mouth indicates the abundance of insects utilized as prey by certain vertebrates such as salamanders, tree frogs, lizards, and many resident and migratory birds. The site is also utilized for avafaunal nesting and breeding. In the 1989 survey by Earth Metrics, no sightings of the endangeredSan Francisco garter snake were made, although this snake was observed at nearby Denniston Creek. The mouth reach is classified as a riparian corridor under the strict meaning defined by the San Mateo County Local Coastal Plan[5]
^U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map 2012-03-29 at the Wayback Machine, accessed March 15, 2011
^(PDF). Archived from the original (PDF) on 2007-07-21. Retrieved 2007-02-01.
^Geoconsultants Inc., Annual report 1988-1989: Groundwater Resources, Half Moon Bay, California, prepared for the city of Half Moon Bay (1989)
^Earth Metrics Inc., Arroyo de en Medio mouth survey, Miramar, California, prepared for the County of San Mateo (1989)
^County of San Mateo Local Coastal Plan, San Mateo County Planning Department (1988)
^U.S. Geological Survey Geographic Names Information System: Arroyo De En Medio
January 01, 1970
arroyo, medio, spanish, middle, creek, mile, long, coastal, stream, western, mateo, county, california, rises, western, slopes, montara, mountain, discharges, pacific, ocean, half, moon, location, unincorporated, community, miramar, miramar, beach, watershed, . Arroyo de en Medio Spanish for in the middle creek is a 2 5 mile long 4 0 km 1 coastal stream in western San Mateo County California Arroyo de en Medio rises on the western slopes of Montara Mountain and discharges to the Pacific Ocean at Half Moon Bay at the location of the unincorporated community of Miramar at Miramar Beach The watershed of Arroyo de en Medio consists of relatively permeable sandy soils capable of significant recharge to its aquifers which supply considerable potable water to the local area Arroyo is Spanish for creek de en Medio means literally of in between but a closer more functional translation may be in the middle Mouth of Arroyo de en Medio where it enters the Pacific Ocean Contents 1 Groundwater 2 Mouth 3 See also 4 ReferencesGroundwater editIn the headwaters area coarse grained decomposed granite overlies heavily fractured granitic based bedrock aquifers 2 This upper pocket groundwater complex feeds down basin alluvial fan deposits on the coastal plain These alluvial fans exhibit some characteristics of a confined aquifer but also respond to recharge from precipitation 3 Mouth editAt the mouth of Arroyo de en Medio the stream cuts through a flat marine terrace plain of alluvium forming steep sided banks of approximately 40 degrees with respect to the channel floor the channel floor is about eight meters deep relative to the bank tops Even at the mouth Arroyo de en Medio is considered intermittent since the flow typically ceases in the summer months However there is some summer standing water in the channel near the mouth the result of street runoff from summer irrigation and car washing The stream mouth is clear of canopy vegetation but densely filled with sedges in a marshy setting nbsp Vegetation at the mouth of Arroyo de en Medio The streambed at the mouth is essentially covered by water dependent plant species These include willow Salix sp sedge Carex sp stream monkey flower Mimulus sp and red alder Alnus oregona 4 These and other riparian plants form the food resource of many faunal species either directly or indirectly Many orb web weaving spiders at the mouth indicates the abundance of insects utilized as prey by certain vertebrates such as salamanders tree frogs lizards and many resident and migratory birds The site is also utilized for avafaunal nesting and breeding In the 1989 survey by Earth Metrics no sightings of the endangered San Francisco garter snake were made although this snake was observed at nearby Denniston Creek The mouth reach is classified as a riparian corridor under the strict meaning defined by the San Mateo County Local Coastal Plan 5 37 29 35 N 122 27 36 W 37 492996 N 122 459977 W 37 492996 122 459977 6 See also editDenniston Creek List of watercourses in the San Francisco Bay Area Naples CreekReferences edit U S Geological Survey National Hydrography Dataset high resolution flowline data The National Map Archived 2012 03 29 at the Wayback Machine accessed March 15 2011 Balance Hydrodgeologics Inc San Mateo County Mid Coast Aquifers Literature Review prepared for San Mateo county Board of Supervisors 2002 PDF Archived from the original PDF on 2007 07 21 Retrieved 2007 02 01 Geoconsultants Inc Annual report 1988 1989 Groundwater Resources Half Moon Bay California prepared for the city of Half Moon Bay 1989 Earth Metrics Inc Arroyo de en Medio mouth survey Miramar California prepared for the County of San Mateo 1989 County of San Mateo Local Coastal Plan San Mateo County Planning Department 1988 U S Geological Survey Geographic Names Information System Arroyo De En Medio Retrieved from https en wikipedia org w index php title Arroyo de en Medio amp oldid 1183191721, wikipedia, wiki, book, books, library,
