Lab 10

• • Task A: What is the total length (in kilometers) of this stream network?

4,180.87 km

I used the Summary Statistics tool, with "ReachLen" as the statistics field and "Sum" as the statistics type. This output a table with the total length of stream segments in meters, which I converted to kilometers by dividing by 1,000.

• • Task B: Which administration agency owns the most land in this watershed (by area)?

Private land makes up the most area, but the US Forest Service is the agency with the most.

I calculate these numbers, I created a new column in the shapefile attribute table called "AgencyArea", ran the Calculate Geometry tool on the shapefile to calculate the total area of each polygon and output those numbers to the "AgencyArea" column, then ran the Summary Statistics tool to calculate total area by owner.

• • Task A: How many different classes (CLASSNAME) of land are there in this raster?

According to CLASSNAME, there are 123 unique classes.

Perhaps this is sort of cheating, but I went to the Symbology tab, selected "Unique Values" in the Primary Symbology tab, and recorded the number of values listed when I set the ID field to "CLASSNAME".

• • Task D: What is the resolution of this DEM (in meters)?

The resolution of this raster is ~9m (note the file name lists 10m).

To figure this out, I opened the "Properties" pane by right clicking the layer in the TOC, and then went to the "Source" tab. Under "Raster Information", it lists the cell sizes as 9 x 9, and under "Extent", it lists the units as meters.

• Task A: What is the mean slope (iGeo_Slope) of the entire network?

The mean slope is 0.03049845 degrees.

To calculate this, I ran the Summary Statistics tool on the layer with the field as "iGeo_Slope" and the statistic type as "Mean".

• Task B: How many reaches (each row is a reach) have an expected beaver dam capacity (occ_EX) over 10?

2,855 reaches have an expected capacity of over 10.

I opened the layer attribute table, then ran the Select Layer by Attribute tool with selection type set to "New selection", and the expression as "oCC_EX is greater than 10". This selected only rows where oCC_EX was greater than 10. The number of selected rows was shown in the bottom left corner of the attribute table.

• Task B: What is the total length of reaches that are within USFS land and on which dam building is possible (oPBRC_UD)?

331.57 km

First, I ran the Select Layer by Attribute tool on the streams layer to select only the streams on land where dam building is possible, and I saved that selection as a new layer. Then, I ran the Select Layer by Attribute tool on the Management Agency layer to select only the land owned by the US Forest Service. Using that selection, I ran the Select Layer by Location tool on both the new stream layer and the management agency layer, and set the tool to the settings depicted to the right. I saved this selection as a new layer. Then I ran summary statistics on the new layer following the same steps as laid out in Part 1: Task A to calculate total stream length.