The Watershed
description
Transcript of The Watershed
The Watershed
The Lower Coquille Watershed is 1059 Sq. miles in area, it is the largest watershed to originate in the Oregon Coastal Range.
The majority of the watershed lies within Coos County, with small areas touching on Douglas and Curry Counties. The river contains three major tributaries; the North, the
Middle, and the South Forks. They join the mainstream, and flow into the Pacific Ocean at Bandon1.
Watershed Location
Coquille Watershed is in Coos County with sections in Douglas and Curry Counties
General GeologyThe Coquille Watershed was created by a combination of events that occurred following
the last Ice Age. A high sea level caused the valley to be clogged with sediments to give a series of valley-fill materials which form the Coquille Formation. The Watershed is
comprised primarily of deep, silty loams, silty clay loams, and clay loams which is prone to erosional processes. An exception to this exists on former marine terraces which are
comprised of sandy and sandy-loam soils. These areas are prone to wind erosion as well as water erosion2.
Most of the formations are sandstone; however, the Looking glass formation is conglomerate at the bottom and transitions to sandstone at the top. The various bedrocks
shown all have naturally high sedimentation rates3.
Hydrologic Summary
Total Drainage Area (sq meters): 269,258,378 m2
Total Drainage Area (sq. kilometers): 269.25 km2
Total Length of Watershed (sq. kilometers): 28.317 km Total Width of Watershed (sq. Kilometers): 23.93 kmWatershed Length/Width Ratio: 1.183Total Number of Subbasins in Watershed: 12Average Area of Subbasins in Watershed: 22.438 km2
Total Number of Stream Segments or Tributaries in Watershed: 1613Total Number of First Order Stream Segments: 815Total Number of Second Order Stream Segments: 381First Order Stream Frequency (total number/Drainage Area: 3.03 per km2
Watershed Parameters
Minimum Watershed Elevation-0 Meters Maximum Watershed Elevation-516 Meters Minimum Slope (decimal degrees)-0 degrees Maximum Slope (decimal degrees)-59.50 degrees
Conclusions
Currently the population within the watershed is about 16, 801 people. The population is concentrated in the valley areas with the majority of clustered
around the incorporated towns of Bandon, Coquille, Myrtle Point and Powers. The more densely populated areas are confined to the flood plains along the
main stems of the watershed. The watershed contains a large area for agriculture and forestry production. In fact the large Coos Bay timber industry
grew up because of the timber out of the watershed area5.
Bedrock Geology of the Coquille Watershed
References Cited
1.Coquille Watershed Association http://www.coquillewatershed.org/Coquille_Facts.html2.Natural Resources Conservation Service http://www.or.nrcs.usda.gov/programs/csp/csp_data/2005/coquille-factsheet.pdf3.Pacific Coast Watershed Partnership http://www.pacificwatersheds.net/coastalnetwork/coquille.htm4.Pacific Coast Watershed Partnership http://www.pacificwatersheds.net/coastalnetwork/coquille.htm5.Introduction to the Coquille Watershed http://www.coquillewatershed.org/Coquille_Facts.html
Lower Coquille Watershed
Prepared by:
Sandi Biester, Mark Johnson and Richard LowesES 341 Fundamentals of Geographic Information Systems
You can insert
Lower Coquille Watershed Vegetation
Physiography
Approximately 70% of the Watershed is Forested. The coniferous forests on productive soils and slopes in the basin are mostly Douglas Fir; however, Port Orford Cedar is also an important component of the forests. In the lowlands the forests are made-up of oak savannas in the drier areas and Douglas Fir, cedar and hemlock in the wetter areas. Land uses in the valley areas are mostly residential and industrials sites, crop and pasturelands, and gravel extraction. Pastureland does extend into the hills above the flood plains in some areas. The steep slopes above the valleys are very sparsely populated. Timber production, agriculture and some mining are the predominant land uses4.
Soil classification of the Coquille Watershed
Lower Coquille Annual Precipitation
Lower Coquille watershed DRGLower Coquille Watershed DEM
Lower Coquille DOQ