Mill Creek/ Umpqua River Watershed
Prepared by:
Brenna Susee and Alyssa Marquez
G.I.S.
Physiography Cont
INTRODUCTION
The Mill Creek/ Umpqua river watershed is located completely
within Douglas County and covers about 348,166,100 m2. Which is in
the southwestern region of Oregon.
Recent timber harvests in the area have begun to occur, as also
seen in Figure six, as the little light green areas. The climate is a
Mediterranean climate with a wet winter and a dry hot summer. The area
is very wet and the highest months for precipitation are November and
December averaging about 11 inches. Precipitation annually ranges from
high to low, low being 0.6in and high being 12in. The precipitation can be
seen in figure 7.
Figure 4. DEMs
Figure 5. DRGs
Figure 1. Map of Oregon and
Mill Creek/Umpqua River
Watershed
Figure 9. Soils
Figure 8. Geology (Bedrock)
Hydrologic Summary
The Water shed lies in three different Quads named, Deer Head
Point, Scottsburg, Devils Graveyard, Elk Peak, Loon Lake, Old Blue,
Golden Falls, Ivers Peak and Kelley Butte. There are two major rivers
that feed the watershed the south and the north Umpqua rivers. There
are over 26 sites where streams poor into or add to the Umpqua River.
Watershed Location
The watershed is located in Douglas county and flows from the
Cascades until it reaches the end of Douglas county. The Umpqua river
flows all the way to the ocean however the end of the river is not
included in this watershed. It was formed through the North and South
Umpqua rivers that drain off the cascades. This watershed and river flow
through the coast range. It is located South of the Willamette Valley.
Figure 10. Streams on
Precipitation
Figure 11. Streams
Conclusions
Figure 6. Vegetation
Figure 2.
Watershed
Figure 7. precipitation
Figure 3. Quad’s Watershed is
located in.
General Geology
The Mill Creek/ Umpqua Watershed is mostly an area devoted to the
Umpqua National Forest and the rest is farmland or becoming a place
where clear cutting is very prevalent. There are many streams fueling
this watershed and most of them are caused from run-off and snow
melt. The watershed in located completely in Douglas, Co. and is a
pretty large one as well.
Physiography
The elevation of the watershed changes from ~360 ft above sea level
to at sea level, as shown in Figure 4, the digital elevation model. As you
can see in Figure 6 a large area of the watershed’s vegetation mostly is
comprised of Douglas Fir and Western Hemlock Trees. Mixed conifer and
broadleaf deciduous forests cover the other large portion especially in
the southwestern part of the watershed.
The four types of bedrock geology located in the watershed are OW,
Tss, Tt, and Ty, marine sedimentary rocks located more in the northern
part of the watershed near Elkton. The soils were formed through a mix
of metamorphic, sedimentary and volcanic rock. Over more than 150 soil
types have been identified in the region. The middle of the region is rich
in deep alluvial or heavy clay materials and other areas are mixed
alluvial, silt or clay structures.
References
OregonGeology GIS Data: Dr. Taylor’s website
Coast Watershed GIS Data: Dr. Taylor’s website
Coast Streams GIS Data: Dr. Taylor’s website
Precipitation GIS Data: Dr. Taylor’s website
DEM GIS Data: UO Libraries
DRG GIS Data: UO Libraries
Roads GIS Data: ODOT
Soil GIS Data: Soilmart