Utilizing BASINS to Calculate Pollutant Loads in the Logan River and Their Effect on the Distribution of Cutthroat Trout

 

Dan Child

d.child@comcast.net

CEE 5440/6440 – GIS in Water Resources

Department of Civil and Environmental Engineering

Utah State University

Fall 2003

 

Introduction:

The Logan River originates in the mountains of southeastern Idaho and carves its way through the Bear River Range into northern Utah.  It flows through scenic Logan Canyon and eventually empties into the Bear River in Utah’s Cache Valley.  The river supports a popular trout fishery and is home to four trout species, including rainbow (oncorhynchus mykiss), brook (salvelinus fontinalis), brown (salmo trutta), and Bonneville cutthroat (oncorhynchus clarkiu utah).  The Bonneville cutthroat trout is a sensitive species which has undergone formal analysis for listing as a threatened and endangered species

 

Trout species are unevenly distributed throughout the river.  Brown and rainbow trout are prevalent in the lower and middle reaches of the river, while cutthroat trout are primarily located in the middle and upper reaches.  Brook trout are found exclusively in the river’s upper reaches.  Because cutthroat trout is a sensitive native species, I’m particularly interested in studying the factors influencing the exclusion of the species from the lower reaches of the Logan River.  Unfortunately, there is currently no data concerning the extent of the range of cutthroat trout in the Logan River.  But as a general rule, cutthroat trout become scarce or nonexistent within the lowest 6 miles of the Logan River (the total length of the river is approximately 40 miles).

 

 

Objective:                                                                                                                                      

The purpose of this project is to estimate pollutant loads in the Logan River.  The results may then be used to assess whether the distribution of trout species within the river is related to pollutant loading.  I will also address other factors that may influence the distribution of cutthroat trout.

 

 

Data Sources:

My main data source is BASINS (Better Assessment Science Integrating Point and Non-Point Sources).  BASINS is a multipurpose analysis system distributed by the U.S. Environmental Protection Agency (EPA) for use in watershed and water quality studies.  It supports the analysis of a wide range of pollutants at a variety of scales.  BASINS also provides the user with multiple tools, ranging from relatively simple to quite complex, which facilitate watershed and water quality analysis.                                                                                                                                                                                                                                                                                                                                                                                               

BASINS allows users to download a large amount of data for any location of interest within the United States.  The BASINS database contains information regarding land use, water quality, river reach data, soils data, weather station data, etc.  It also provides the capability to import NHD river reach information directly into a project.                                                                                                

 

In addition to data provided by BASINS, I also utilized data from the National Elevation Dataset (NED) and the National Hydrography Dataset (NHD) in this project.

 

 

 Study Area

My study area falls within the Little Bear River Watershed (HUC# 16010203).

                                                                                                                                                       

                                                 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

My study area will commence at the headwaters of the Logan River and its tributaries and will proceed downstream to the junction of the Logan River and the Blacksmith Fork River, as shown below.

 

 

 

 

 

 

 

 

 

 

 

       

         

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Building a BASINS Project

I began this project by downloading BASINS files from the BASINS website, which is supported by the EPA.  Basins data is organized into four main categories:

1 – A core dataset

2 – A DEM dataset

3 – A DEM grid dataset

4 – PCS3 files

 

The core dataset contains all of the information necessary to get started.  I began by downloading the data and then projecting it using the BASINS Data Projector.  Once the data was projected I was then able to build my project using the BASINS Project Builder.  The Project Builder creates a project file which can then be viewed and analyzed using BASINS.

 

 

Additional Data

Land use data will be necessary to model pollutant loads, so I first added land use information to the project.  The BASINS core data provides three separate land use files within the HUC, two of which contain land use data within my study area.  I merged these two files to create a single data layer covering my entire study area.  The result is shown below:

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

              

            

 

 

 

In order to model pollutant loading it’s first necessary to delineate subwatersheds.  In order to do this I needed to add a Digital Elevation Model (DEM) to my project.  I was informed by Dr. Tarboton that data from the National Elevation Dataset (NED) is likely more recent than BASINS DEM data, so I downloaded DEM files from the NED website and added a DEM to my project. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                 

 

 

 

In addition to a DEM, an NHD reach file is also necessary in order to delineate subwatersheds.  BASINS contains an “NHD Download” tool which enables the user to import NHD information directly into a BASINS project.  I used the tool to add a river reach layer to my project.  The result is shown below:

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

      

     

     

 

 

 

Watershed Delineation

My next step was to perform a watershed delineation for my study area.  I used the “automatic delineation” tool to do this.  I entered the following specifications into the delineation properties:

 

·         Select the “burn_in option” and specify NHD reach file as the file on which the new delineation reach file will be based.

·         Select the HUC boundary as the boundary for the delineation.

·         Enter a 1500 hectare threshold for the stream definition.

 

Shown below are the results of the watershed delineation.  The entire watershed is now divided into subwatersheds, each with a corresponding outlet.  It should be noted that it’s possible to select only a portion of the watershed for subwatershed delineation, I simply chose to select the entire watershed.

 

 

 

 

 

 

 

 

 

 

 

 

                                                                                                                                                                                                                                                                                                                                                                                         

 

 

 

 

 

 

 

 

 

 

 

 

 

PLOAD

The project is now ready to support PLOAD, which is a model designed to calculate pollutant loads for watersheds and subwatersheds.  The model uses land use data to estimate pollutant loads.  It is a good planning level model, which also allows the user to evaluate the effectiveness of Best Management Practices (BMPs).  The model does have its limitations, however.  Limitations include: inability to account for pollutant sources other than land use, inability to simulate daily or monthly pollutant loads, and inability to simulate in stream processes such as hydraulics and nutrient decay.  So in short, PLOAD is a good model for obtaining a broad overview of pollutant loading, but it isn’t necessarily a good tool for site-specific analysis.  In fact, PLOAD data is often used by more complex models for more site-specific analysis.

 

PLOAD has two options for calculating non-point source pollution: 1) the Export Coefficient Method, and 2) the Simple Method.  The Simple Method is intended for use in heavily urbanized areas and therefore isn’t applicable to my project.  Instead I chose the Export Coefficient Method, which uses the following equation to calculate pollutant loading:

 

LP= ∑U ( LPU * AU )

 

where

                LP   = Pollutant load ,lbs

                LPU = Pollutant loading rate for land use type U, lbs/acre/yr

                AU  = Area of land use type u, acres

                       

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

      

 

Parameters:

There are eight parameters to specify in PLOAD, which are as follows:

1. Name of PLOAD session

2. Watershed Boundary Data Set.  I used the HUC boundary layer.

3. Select Watershed.  I selected all subwatersheds adjacent to the Logan River within my project area.  The   selected subwatersheds are highlighted below.

                                                                               

                                                                                           

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

4. Landuse Data Set.  I selected the landuse file that I created by merging two of the original files provided by BASINS.

5. Calculation Method Setup.  I chose the Export Coefficient Method.  I then referenced an Excel executable file and imported tabular landuse data from an EMC table in Excel, which contains pollutant coefficient values.   I then selected the following pollutants for evaluation: BOD, COD, TSS, TDS, NOX, TKN, NH3, TP, and DP.  The EMC table is shown below:

                                                   

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6. Best Management Practices.  Not used in this project.

7. Point-Source Pollutants.  Not used in this project.

8. Pre-Existing Data Set.  Not used in this project.

 

 

Output

I’m now able to “Run Calculations.”  PLOAD then produces an output table and two layouts for each pollutant showing annual pollutant loading resulting from each subwatershed, as well as per acre pollutant data for each subwatershed.  It also provides an interactive view displaying both the output table together with the subwatersheds.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

    

 

 

        Figure 10: PLOAD output

 

Shown above is the interactive output table with the accompanying subwatershed.  The user can select subwatersheds on the map to obtain information about each subwatershed, or, when one selects a row in the table, the corresponding subwatershed is highlighted.  This provides the user with an organized interface for analyzing data about each subwatershed.

 

Output table

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                                      

 

 

 

 

    

    Figure 11: Output table

 

Shown above is the resulting output table.  The table contains pollutant loading data for each of the subwatersheds selected for the analysis.  The pollutant loading data is contained in columns which are labeled as described below:

 

AR_Pollutant = annual load per unit area (pounds per acre)

LD_Pollutant = the annual load in pounds, where the word “Pollutant” is replaced by the pollutant name.

 

Pollutant Layouts

PLOAD creates two layouts for each pollutant selected in the analysis.  The first layout depicts the total annual load in pounds, and the second layout depicts the annual load per unit area.  Shown below are the results of the layouts created for the NH3 pollutant (ammonia).  Similar layouts were created for each of the remaining eight pollutants I selected earlier, resulting in a total of 18 layouts created in this project.  Rather than display each of the layouts here, I’ll summarize the results in the conclusions section of this report.

 

 

 

 

 

 

 

 

 

 

 

 

 

           

 

                 

 

 

 

 

Conclusions

After analyzing the results of PLOAD I was able to determine that, at minimum, the Logan River contains significant accumulation of the following pollutants: BOD, COD, NOX, NH3, TP, DP, TSS, TDS, and TKN.  Furthermore, I was able to determine that the loading of ammonia (NH3), phosphorus (TP), and nitrogen oxides (NOX) may play an particularly important role in the exclusion of cutthroat trout in the lower reaches of the Logan River.  Data for each of these pollutants is as follows:

 

Ammonia:

Ammonia is a particularly toxic pollutant to trout.  60,000 pounds of ammonia are added to the Logan River each year.  Of particular importance is the fact that more than one-third of the river’s entire annual loading of ammonia results from the lowest six miles of the river (the total river length is approximately 40 miles).  The lowest six miles of the river also happens to be the area in which cutthroat trout are scarce or nonexistent. 

 

Phosphorus:

There are 70,000 pounds of phosphorus added to the river annually.  Interestingly, well over half of the annual phosphorus loading also results from the lowest six miles of the river.

 

Nitrogen Oxides:

115,000 pounds of nitrogen oxides are added to the river each year.  Nitrogen oxides have been shown to cause a wide range of harmful effects in various trout species.

 

As a result of my modeling, I’m able to conclude that pollutant accumulation in the Logan River’s lower reaches may play a role in the exclusion of Cutthroat trout.  However, it’s apparent that more research is necessary in order to validate this hypothesis.  In order to accurately assess the impacts of pollutants on the distribution of Cutthroat trout in the river, future work may include:

 

·         Conduct enhanced water quality modeling to better estimate pollution content in the river.

·         Create extent of species data for Bonneville cutthroat trout in the river (currently nonexistent).

·         Integrate gamefish stocking data from the Division of Wildlife Resources (DWR) into the project.

·         Collaborate with other disciplines to assess biological impacts on Cutthroat distribution.

 

 

Notes

It should be noted that this project was intended to provide a broad analysis of pollutant loading in the Logan River.  Other sources of pollution exist which were not analyzed in this project.  These sources may include: U.S. Highway 91, other roads, and point source pollution.  Furthermore, aside from pollution, there likely are other factors affecting Cutthroat distribution in the river, which may include: gamefish stocking, competition from other trout species, hydraulics, and biological factors.

 

 

Acknowledgments

I would like to thank Bethany Nielsen at USU’s Institute for Natural Systems Engineering (INSE) for her help with running and understanding BASINS.  I’d also like to thank Mark Winkelaar at the INSE for his help with fish data and information.

 

 

References

BASINS website

http://www.epa.gov/OST/BASINS/

 

National Hydrography Database

http://nhd.usgs.gov/

 

National Elevation Dataset

http://gisdata.usgs.gov/ned/default.asp

 

BASINS training materials provided by USU’s Environmental Management Research Center (EMRC)

http://emrc.usu.edu/basins/

 

Utah Division of Wildlife Resources

http://www.wildlife.utah.gov/