There are two types of MRR sites - stream and fixed. A stream site represents an entire stream, or a stream segment, that fits entirely within a 4th level HUC. For example, the main stem Columbia River is divided into 9 stream segments (with site codes COLR1 - COLR9) divided by 4th level HUCs along the river, while Tanner Creek (TANNEC) is entirely within one HUC.

 

 

Stream sites are used when tagging will or can occur anywhere along that stream or stream segment. Instead of registering a new fixed location for each data collection location, the data contributor uses the stream site code and then specifies the location on the stream using river kilometers and, optionally, geographic coordinates. Fixed MRR sites generally represent a permanent human-built structure or prominent geographic feature or a trap that has been permanently placed in a location.

 

All MRR sites are represented in the PTAGIS database by one set of coordinates: for stream sites, the coordinate pair represents the midpoint of the stream; for lakes or other polygons, the coordinate pair represents the centroid of the polygon. PTAGIS also publishes a spatial dataset in which each site is represented by the proper shape type.

 

MRR sites are also assigned a river kilometer address (also known as an RKM). A site's RKM uses a set of integer numbers displayed as triplets to count the number of kilometers from the mouth of the Columbia River to the current site, where each triplet represents a new confluence. For example, the RKM for Hood River is 273 because the confluence of Hood River with the Columbia is approximately 273 kilometers from the mouth of the Columbia. If tagged fish are released at a location 5 km upstream, the data contributor would enter the Release RKM as 273.005. Let's look at a fixed site on one of the Hood River forks: Moving Falls Acclimation Ponds are located 4 kilometers up the West Fork of Hood River, so it's RKM address is 273.020.004. The 020 represents the location of the confluence of the West Fork with the main stem Hood River.

 

 

An MRR site code must be between four and six characters long and can contain a location abbreviation and a site descriptor for the type of location. Established site descriptors are:

 

If a site replicates an already established code, a number will precede the site description. For example, the first Elk Creek defined in PTAGIS will have the code ELKC, the second will have a the code ELK2C, and so on. It is also recommended that the site name have a reference to the parent stream to provide a larger location reference. For example, ELK2C would have the name Elk Creek, tributary to SF Salmon River.

 

If a data contributor is planning to collect data at a location which is not yet defined in PTAGIS, they can request a new MRR site code using these instructions. All defined MRR sites can be viewed on the PTAGIS web site.

Version: 1.07

Published: 9/6/2023