"Latah Creek looking North"
Little Latah Creek, about 10 miles
long, is a generally southwest-flowing stream, and at the
confluence carries almost as much water as Latah Creek. The creek
begins a few miles south of Plummer, and its headwaters are near
the ridge where north-flowing Plummer Creek also begins. U.S.
Highway 95 crosses the creek very near the headwaters, and for its
entire length, it follows Lovell Valley Road. Near the junction of
Idaho State Route 60 and Washington State Route 274, which is the
continuation of Lovell Valley Road in Washington State, it receives
Moctileme Creek, its largest tributary, on the left bank. Moctileme
Creek is about 6 miles long, flowing west from Windfall Pass and
mostly paralleling State Route 60. At this point, Little Latah
Creek has already grown large from agricultural runoff. The creek
then bisects Tekoa, flows underneath Washington State Route 27, and
enters Latah Creek.
Latah Creek Geology
Latah Creek can be divided into three
distinct geological regions; these are a small section of its upper
headwaters, a long and broad valley, and channeled scablands. In
its headwaters, the creek flows through the foothills of the Rocky
Mountains, specifically in those of the Clearwater Mountains. The
topography here are steep ridges and peaks dissected by deep,
forested close-to-bedrock valleys, drained by rocky and steep
mountain streams, with a light covering of soil. After its
mountainous headwaters, the creek passes through the much more
rounded, older Palouse Hills. Below the deep loess in the Palouse
Hills, a basalt layer separates the creek from groundwater, which
finally rises to meet stream elevation at the Washington-Idaho
state border. Most of the creek from where it turns north at
Sanders to about 20 miles upstream of its mouth flows in a broad
and shallow, arid valley atop several hundred feet of alluvial
deposits. In the final 20 miles, the Latah Creek watershed
intersects the Channeled Scablands, which were formed by the
Missoula Floods that inundated the area after an ice dam on the
Clark Fork Pend Oreille River, during the last Ice Age, was
breached. The floods have deposited "terraces", otherwise known as
"backflood deposits", which the creek has eroded through, creating
steep and unstable gravel slopes topped by sheer cliffs. Near
Spokane, the creek turns to the northwest in a nearly straight
line; this is caused by a strike-slip fault named Latah Creek
Fault.
The watershed of Latah Creek covers 673
square miles, stretching from southeast to northwest and straddling
the Washington-Idaho state border. The mostly semiarid basin is
divided mostly among forests and agriculture, with small towns
spread along the length of the creek and its tributaries. The
largest city, Spokane, is located at the junction of Latah Creek
and the Spokane River. Except for its upper headwaters and the
canyon it flows through in its final few miles, the creek flows in
an open plain surrounded by low hills, and originally would form
meanders and braided streams across this wide floodplain. The
conversion of the floodplain to agricultural uses, however, forced
the creek to flow in a straighter course. As a result, erosion and
turbidity in the creek has increased, while water quality and
habitat have decreased. At its mouth, Latah Creek has been known to
contribute up to 90 percent of the flow of the downstream Spokane,
and as low as 1 percent.
The Latah Creek watershed is dominated
by agriculture, which has diverted the creek and its tributaries
for irrigation. This has caused the ruin of forests, riparian
zones, and natural flow patterns. The creek has been channelized in
some places, and meanders, islands and natural channel formations
have been destroyed. In response to these damaging factors, the
water quality overall in the Latah Creek basin is quite low, and
"Washington State water quality standards for temperature,
dissolved oxygen, pH, and fecal coliforms are routinely violated."
The remaining third of the land in the watershed is mostly
forest.
The small drainage divide on the east
side of the watershed separates Latah Creek from streams draining
into Coeur d'Alene Lake and the St. Joe River, including Plummer
Creek. Tributaries flowing off this divide into Latah Creek
(right-bank tributaries) include Little Latah Creek, Rattlers Run
Creek, Rock Creek and California Creek. Left-bank tributaries
include Marshall Creek and North Pine Creek. The watershed is
bordered on the south by that of the Palouse River, and on the
west, Hole-In-The-Ground Creek, a tributary of the Palouse, and on
the northwest, Deep Creek, a tributary of the Spokane. Roads
paralleling Latah Creek include (from mouth to headwaters) U.S.
Highway 195, Latah Creek Road, Spangle-Waverly Road, Washington
State Route 27, and Idaho State Route 95. There are no dams on the
mainstem of Latah Creek.
Agricultural land use covers 212,880
acres of the Latah Creek watershed, followed by 119,490 acres of
forest. Urban areas within the Latah Creek basin cover only 12,565
acres . Because of its importance as a tributary to the Spokane,
the pollution in Latah Creek directly affects the Spokane
downstream of their confluence. The only Spokane River tributary
larger or equal in size to Latah Creek is the Little Spokane River,
which joins about 10 miles downstream of Latah Creek. Although
there are larger tributaries upstream of Coeur d'Alene Lake, the
source of the Spokane River (including the St. Joe River and the
Coeur d'Alene River) those do not directly feed the Spokane.
Resources: www.wikipedia.org, "Latah
Creek".
To claim
this Earthcache you will have to answer the following questions.
Please email me (AmplePeach@gmail.com) the answers. Please do not
post answers in your log, If answers are posted, your log could be
deleted without warning. Sorry, but this is to make the find fair
for all.
1. To start your lesson please visit
the above coordinates. The answers to questions 2, 3, 4, 5, 6 &
7 can be found here.
2. Determine the flow rate of the creek
at the time of your visit. This may be done by measuring &
marking a distance along the river bank or on top of the bridge,
then tossing in a stick up creek from your starting point. With a
stop watch, time how long it takes your stick to complete your
measured distance course. Then calculate that into "Feet Per
Second" for the river (Distance divided by Time).
3. What color is the creek? Why do you
think its this color?
4. From the posted coordinates you will
see a basalt rock on the west side of the creek. Determine the
distance between the top of the rock and the creek at the time of
your visit.
5. Estimate the width of the creek from
the posted coordinates.
6. Explain how you would clean this
creek of pollution. Obviously stopping agriculture is not an
option, be creative.
7. Provide the time of day and weather
conditions at the time of your visit.
Although not a requirement a photo
of yourself near the site would be appreciated.
:)
Please note that I will not be
responsible for personal injury or damage to your equipment. Please
be careful when you are near the creek. Thank
you!