Step 1 - Map of Logan River Watershed

Step 2 - Longitudinal Profile

The longitudinal profile of the Logan River from the headwaters at Franklin Basin (around 42.0353,-111.599127) down to the mouth (around 41.741216, -111.938460) was extracted from the supplied Logan River mainstem .kmz file in Google Earth Pro.

What is the base-level control of the Logan River today?

According to the profile graph in Figure 3, today's base level elevation of the Logan River is 1344 m. This base level is controlled by the confluence of the Logan River with the Little Bear River, which is located in Cache Valley. This profile also shows that the Logan River has an average 1.6% slope.

What was the base-level control of the Logan River about 18,000 years ago?

Lake Bonneville was present about 18,000 years ago, which was the base-level control of the Logan River. The elevation of the shoreline was about 1500 m after doing a quick Google Search.

What is the mainstream length of the Logan River in km?

The mainstream length of the Logan River is 82.2 km from Franklin Basin to the mouth of the river at the confluence with Little Bear River. This calculation was determined using the Logan River mainstream shapefile based on Figure 3 using Google Earth Pro.

What is the concavity?

Concavity = 2A/H where A (m) is the height difference between the profile at mid-distance and a straight line joining the end points of the profile and H (m) is the total fall of the longitudinal profile.

For the Logan River:

H = 2465 m - 1344 m = 1121 m

Midpoint = 82.2 km/2 = 41.1 km = 41100 m

Elevation at Midpoint = 1560 m

Straight line joining the end points of the profile = ~1900 m (with more time I would love to learn how to find this value without estimating it using the longitudinal profile).

A (m) = 1900 m - 1560 m = 340 m

Concavity = 2A/H = (2*340)/1121

Concavity = 0.61

*Note-- methodology for finding the straight line joining the end points of the profile is shown in Figure 4.

Label any knickpoints and pose a working hypothesis about the controls.

Control Hypothesis: A beaver dam could be the reason for where Knickpoint 1 was identified which is about 74.8 km from the mouth of the Logan River. This dam would cause sediment to be deposited behind the dam, indicating a knickpoint on the longitudinal profile. Knickpoint 2 represents where Second Dam is located which is about 34 km from the mouth of the Logan River. Knickpoint 3 represents where First Dam is located which is about 31.2 m from the mouth of the Logan River. Because sediment is again being deposited behind these dams, knickpoints occur in the longitudinal profile.

Step 3 - Catchment Morphometrics

What is the catchment length in meters?

The catchment length is about 59,459.91 m or 59.46 km based on using the measuring tool in Google Earth Pro and approximating the valley bottom straight line distance from the mouth of the Logan River to furthest headwaters in Franklin Basin. The methodology is shown in Figure 5.

What is the catchment area in square meter and square kilometers?

The area of the Logan River catchment is 646.56 sq. km (646560000 sq. m) based on the use of the attribute table for the shapefile provided using USGS National Map Viewer.

What is the catchment perimeter length in meter and kilometers?

The catchment perimeter is approximately 154,232.16 m (154.23 km) which was calculated by using the measure tool to measure the perimeter of the catchment in Google Earth Pro from the provided catchment shapefile.

Calculate the circularity ratio.

The circularity ratio (Rc) = A/Ac where A is the catchment area and Ac is the area of a circle with the same circumference as the catchment.

For the Logan River Watershed:

A = 646.56 km2

Perimeter = Circumference = 154.23 km

Radius = 24.55 km

Ac = 1893.45 km2

Rc = 646.56 km2 /1893.45 km2

Circularity Ratio = 0.34

Calculate the elongation ratio.

The elongation ratio (Er) = (A^(0.5))/L where A is the catchment area and L is the catchment length along its axis.

For the Logan River Watershed:

A = 646.56 km2

L = 59,459.91 m or 59.46 km

Er = (646.56 km2)^(0.5) / 59.46 km

Elongation Ratio = 0.43

Calculate the form factor of the Logan River Watershed

The form factor (Rf) = A /(L^2) where A is the catchment area and L is the catchment length along its axis.

For the Logan River Watershed:

A = 646.56 km2

L = 59.46 km

Rf = 646.56 km2 / (59.46 km^2)

Form Factor = 0.18

What is the catchment relief of the Logan River Watershed?

The catchment relief (H) is defined as the difference between the elevation of the catchment mouth Emin and the highest peak in the catchment Emax.

For the Logan River Watershed:

Emin = 1344 m (confluence with Little Bear River)

Emax = 3043 m (Naomi Peak)-- I figured this out by using Google Earth Pro for visualizing the highest peak as well as doing a quick Google Search for the highest peak in the Bear River Range

H = 3043 m - 1344 m

Catchment Relief = 1699 m

What is the relief ratio of the Logan River Watershed?

The relief ratio (Rh) = H/L where H is the catchment relief and L is the catchment length along its axis.

For the Logan River Watershed:

H = 1699 m

L = 59,459.91 m

Rh = 1699 m / 59,459.91 m

Relief Ratio = 0.029

What is the drainage density of the Logan River perennial drainage network?

The drainage density (Dd) is measured as the total length of stream channels (km) per unit area of a catchment (km2). I used the attribute table of the Logan Perennial Networks shapefile to find the total length of the stream channels in kilometers.

For the Logan River Watershed:

Dd = 216.68 km / 646.56 km2

Drainage Density = 0.34

What is the drainage patter of the Logan River Network?

The drainage pattern of the Logan River Network can be described as young and dendritic. However, I am thinking it could possibly be described as trellis towards the furthest headwaters in Franklin Basin. Dendritic drainage patterns develop in areas of homogenous terrain in which there is no distinctive geologic control. Trellis drainage patterns are indicative of both a strong regional dip and the presence of folded sedimentary strata.

Step 4 - Stream Order

What is the stream order of the Logan River at its mouth?

The stream order at the mouth of the Logan River is 4. This was completed using the Horton-Strahler approach to stream ordering and based on the Logan Perennial shapefile provided which was loaded into the USGS National Map Viewer.

What is the stream order of the Temple Fork River at its mouth?

The stream order at the mouth of the Temple Fork River is 3. This was completed using the Horton-Strahler approach to stream ordering and based on the Logan Perennial shapefile provided which was loaded into the USGS National Map Viewer.

What is the stream order of Beaver Creek?

The stream order of Beaver Creek is 1. This was completed using the Horton-Strahler approach to stream ordering and based on the Logan Perennial shapefile provided which was loaded into USG National Map Viewer.

Does the Logan River appear to obey the Hortonian laws of stream network composition?