Introduction

1. Kilchis Watershed of Tillamook County, OR Prepared by: Spencer Helwig &Trevor Brown ES 341 Introduction The Kilchis Watershed is an important watershed that is mostly driven by the Kilchis River which flows West into the Tillamook Bay. The Kilchis Watershed is composed of 13 subbasins. Physiography The landscape present in the Kilchis watershed is mountainous terrain in the Coast Range, with the Kilchis River being the defining characteristic of the watershed. The watershed has a minimum watershed elevation of three feet and a maximum watershed elevation of 1,006 feet. The minimum slope is 0 decimal degrees and the maximum slope is 72.8 decimal degrees. A variety of vegetation exists. The ones prominent existing are evergreen forests, red alder forests, mixed conifer and deciduous forests, and agriculture. This is reflected in the amount of rainfall the Kilchis Watershed receives over the year on average, with the peak rainfall of 200 inches. Hydrologic Summary The Kilchis Watershed covers a total drainage area of 168,153.9 sq. km, total width of 11.4km, and total length of 22.2km. The watershed is composed of 13 subbasins, and the average area of a subbasin covers 12.9 sq. km. The total number of streams in the watershed is 1,171, with the number of first order segments being 870 and the number of second order segments being 413. On average, there is one first order stream for every five sq. km. Watershed Location The Kilchis Watershed is located North of Tillamook in Tillamook County, OR. General Geology The Kilchis Watershed has 4 different surface deposits: Qal, Tsd, Ttv, and Ttvm. The Qal geocode stands for river alluvium deposits of Holocene age, the Tsd geocode stands for sedimentary rocks of Oligocene to upper Eocene age, the Ttv geocode stands for Tillamook volcanic rocks of Eocene age, and the Ttvm geocode stands for marine facies. The most common soil in the Kilchis Watershed is the Necanicum-Ascar-Klootchie Complex with 60 to 90% slopes. Conclusions By examining the Kilchis Watershed, using ArcGIS, it becomes clear to observe specific spatial information regarding it’s boundaries, subbasins, vegetation, geology, roads, elevation, streams, wetlands, and precipitation in regards to this specific area. More rainfall occurs in areas of higher elevation, agriculture exists in the lowlands of the watershed which also happen to be made up of alluvium deposits, and that the roads follow the waterways in the watershed. The skills used in creating this poster include: the collection of GIS data from online sources, defining and transforming projection systems, clipping, dissolving, mosaicing, and displaying data, as well as problem solving and data transfer. References Cited http://www.oregon.gov/DAS/EISPD/GEO/alphalist.shtml http://www.or.nrcs.usda.gov/pnw_soil/or_data.html http://libweb.uoregon.edu/map/map_section/search.html http://www.co.tillamook.or.us/gov/gis/default.htm