The quality of our environment and particularly our water has become a matter of interest to many people. The quality of our water is a direct indicator of the health of our environment. In Texas, river authorities have been charged with monitoring the water quality of the river basins. The Lower Colorado River Authority (LCRA) oversees the lower Colorado River watershed. One program that the LCRA has initiated to help monitor and protect the water quality of the Colorado River is a volunteer citizen water quality monitoring program called the Colorado River Watch Network (River Watch).
The emphasis of my project is on monitoring data collected by the volunteers and staff of the River Watch program. Currently the River Watch is maintaining approximately 50 active monitoring sites throughout the lower Colorado River basin. These sites are being monitored by about 30 schools and 40 citizen monitors. Water quality monitoring in the Austin area is particularly strong with a coalition of water monitoring groups coordinated by the Austin-Area Volunteer Monitoring Coalition. The River Watch is part of this coalition along with the City of Austin's Water Watchdogs, Travis County's Creek Watch, the Austin Youth River Watch, and the TNRCC's Texas Watch.
A number of different organizations and government entities operate professional water quality monitoring sites in the Colorado River watershed and particularly in the Austin area. There are active water quality monitoring programs by the United States Geological Survey (USGS), the Lower Colorado River Authority, the Texas Natural Resource Conservation Commission (TNRCC) and various departments of the City of Austin.
For several years I volunteered as a citizen water monitor for the River Watch gathering data at a site on Town Lake on a weekly bases. I was inspired by the fact that the River Watch program gets citizens involved in monitoring the quality of the environment, increases people's awareness of their watersheds, and gives them a sense of personal responsibility for protecting their water. The River Watch is doing an excellent job of getting citizens involved in water monitoring and the amount of data is growing daily.
The following is the mission statement of the River Watch which leads to the goal of this project:
Mission Statement of the Colorado River Watch Network
"The mission of the Colorado River Watch Network is to encourage and support community-based environmental stewardship by providing citizens, teachers and students with the information, resources and training necessary to monitor and protect the waterways of the lower Colorado River watershed. Combining water quality monitoring instruction with "hands on" laboratory and field experience motivates students and citizens to become active in local environmental issues. River Watch succeeds because it serves a public desire to be involved in environmental management and because it recognizes the value of credible data. Following careful training and quality assurance techniques, River Watch volunteers collect meaningful water quality information. Data collected by the monitors is used by the Lower Colorado River Authority to supplement its own professional monitoring efforts. Network monitors also serve as an early warning system for environmental threats. Data is available for public review and has been used toidentify areas of concern for professional investigation. In recognition of the volunteers' commitment, every year CRWN provides a site-specific data report for each monitor who regularly collects and submits data."
This term project is the initial step in exploring ways that GIS programming can assist the Colorado River Watch Network in achieving the following aspects of it's mission:
1) Demonstrating the credibility of the monitoring data
2) Providing an environment to effectively integrate the volunteer monitoring data with professional monitoring data
3) Developing methods to use the data in GIS as a potential "early warning system for environmental threats".
4) Developing methods to use the data in GIS to generate site-specific data reports for each monitor with long-term trends and spatial graphics showing the trends at other near-by sites.
The objective of this term project is to create a model GIS project in which citizen water quality data can be easily accessed and viewed in relation to the spatial environment. Water quality data from the USGS is also used. The methods of processing the data and setting up the GIS project are described in detail so that others interested in this method of working with water quality data can reproduce it.
The model watershed chosen is Barton Creek, a watershed in the Austin metropolitan area that is currently under rapid development. It is the focus of much environmental debate and many legal fights. Of particular interest in the watershed is Barton Springs a large natural spring near downtown Austin that has historically been a popular place of recreation for people living in the area and considered by many to be the "soul" of Austin. The Edwards Aquifer recharge zone cuts across the Barton Creek watershed. The Edwards Aquifer is the source of Barton Springs and is an important source of water for Central Texas. Water quality measurements of the springs are included in the project and the location of the Edward Aquifer recharge zone is available to be viewed.
The GIS software program used is Arc/Info and Arcview, developed by Environmental Systems Research Institute (ESRI)
River Watch Water Quality Data
Volunteers for the River Watch must participate in a three-phase certification process to become water quality monitors. This certification process is modeled after the TNRCC's Texas Watch program. Monitors use field kits specifically designed for the program and most of the measurements are made at the site.
The following water quality indicators are measured:
USGS Water Quality Data
Water quality data is collected by the USGS using automated sensing devices. Flow data is also collected at each water quality monitoring site. The USGS measures a wide variety of water quality indicators. For this project I have chosen the indicators that best match those measured by the River Watch plus the specific conductivity. The data is available in two different formats over the internet. One is in a single column form for all the data available with a code for each different water quality parameter (LINK to example).
The following image is an example of the format of the USGS water quality data I used downloaded from the USGS web site for Barton Creek at Highway 71 (1995 Station Data Page). The data is organized by "water year" (October-September) and the data is arranged in an orderly table with column headings. The average daily flow data for the site is also available in the same table.
-Weighted Flow Calculations with USGS Data
The USGS data is given in two forms over the year. One is storm event data which is given as a series of sets of water quality measurements over a time period in which the the stream flow increases, peaks and decreases again, a storm event. The second form is baseline data which is a single set of water quality measurements at a one time. A weighted flow calculation was done to the storm flow data so that a single representative quantity for the water quality parameter can be given for that storm event. Below is a image of the spread sheet calculation for nitrates on May 29, 1994 at the Highway 71 USGS site:
For this model I chose a time period that had about average rainfall and Barton Creek was flowing for much of the year, the USGS 1994-95 water year. During periods of drought Barton Creek is dry. I used the USGS Discharge Data for Texas and chose a period during which the creek had some flow for a good part of the year.
First, create a directory in the Alpha system to keep the project files. (Note: Text in italics is copy from the alpha system)
For this project the geographic base map for the Barton Creek watershed was obtained from work being done by Christine Dartiguenave. The procedure that was used to delineate the watershed and streams is described in detail on Dr. Maidment's Spring 1997 GIS Class home page, Exercise 2. Delineation of Watersheds and Streams. 30 meter DEM,s for watersheds in the immediate Austin area are available on CD-ROM. 3 arc-second DEM's for anywhere in the US are available through the USGS web site. Further work with the larger Colorado River watershed will require the use of this data and the delineation of the watersheds and streams.
The coverages used in this project are projected in State Plane coordinates, zone 5376. This is a Lambert conformal conic projection established for legal surveys in Texas.
In Arcview open a new project and import the base map themes for the watershed boundaries and streams.
a) An ID number and the latitude and longitude of each site are the necessary data to create the point coverages. The name and number of the sites are added to the point attribute table after it is created. The USGS site locations in the Barton Creek watershed were obtained from the USGS site information page on the internet. All the coordinates were in geographic degree, minutes, and seconds. For the Barton Creek watershed several of the USGS sites were at the same location (by name) as the River Watch stations but the geographic coordinates were slightly different. At locations with both River Watch and USGS sites the USGS longitude/latitude data was used for both.
If the coordinates are in geographic degrees, minutes, and seconds then it is necessary to convert to decimal degrees since this is the form needed to work within Arc/Info. Use the following equation for the conversion:
Decimal Degrees = Degrees + minutes/60 + seconds/3600 (the west longitude is negative)
Do the conversion the using an Excel spreadsheet and save it for further conversions. See an example spreadsheet below.
b) Create a text file containing the ID information and the longitude/latitude coordinates of the sites. In Text Editor in Arcview open a new file and create a file as shown below:
0500 -97.925280 30.296111 0350 -97.844444 30.273889 0700 -98.024167 30.236944 end
It is important to type "end" and Enter at the end of the file. Save this file as name.dat file (crwnltln.dat in this project).
c) In Arc (Following where you see Arc: is the command to be typed in) create the point coverage for the River Watch sites.
Arc: generate crwn
Generate: input crwnltln.dat (this is the longitude/latitude file that was created)
Creating points with coordinates loaded from crwnltln.dat
Externalling BND and TIC...
Arc: build crwn points Building points...
Arc: addxy crwn
Adding X,Y Coordinates to crwn.PAT
d) Check the point coverages
Arc: list crwn.pat
Record AREA PERIMETER CRWN# CRWN-ID X-COORD Y-COORD 1 0.000 0.000 1 500 -97.925 30.296 2 0.000 0.000 2 350 -97.844 30.274 3 0.000 0.000 3 700 -98.024 30.237
e) Project this point coverage into the same projection as the watershed and stream coverages that are being used. Create a projection file in the text editor and save as a text file (stplprj. in this project). The new point coverage is in geographic coordinates (input) and the desired projection (output) is stateplane, zone 5376. The following is the projection file used for the point coverages.
f) In Arc project the point coverage naming the new coverage crwnstat:
Arc: project cover crwn crwnstat stplprj.
Warning: By selecting STATEPLANE as a projection, the datum will default to NAD27 if not specified.
g) Check the projected file:
Arc: list crwnstat.pat
1 AREA = 0.000 PERIMETER = 0.000 CRWNSTAT# = 1 CRWNSTAT-ID = 500 X-COORD = -97.925 Y-COORD = 30.296 2 AREA = 0.000 PERIMETER = 0.000 CRWNSTAT# = 2 CRWNSTAT-ID = 350 X-COORD = -97.844 Y-COORD = 30.274 3 AREA = 0.000 PERIMETER = 0.000 CRWNSTAT# = 3 CRWNSTAT-ID = 700 X-COORD = -98.024 Y-COORD = 30.237
h) Description of files used in projection procedure:
Arc: describe crwn
Description of SINGLE precision coverage crwn FEATURE CLASSES Number of Attribute Spatial Feature Class Subclass Features data (bytes) Index? POINTS 3 24 SECONDARY FEATURES Tics 4 TOLERANCES Fuzzy= 0.000 N Dangle = 0.000 N COVERAGE BOUNDARY Xmin = -98.024 Xmax = -97.844 Ymin = 30.237 Ymax = 30.296 STATUS The coverage has not been Edited since the last BUILD or CLEAN. NO COORDINATE SYSTEM DEFINED
Arc: describe crwnstat
Description of SINGLE precision coverage crwnstat FEATURE CLASSES Number of Attribute Spatial Feature Class Subclass Features data (bytes) Index? POINTS 3 24 SECONDARY FEATURES Tics 4 TOLERANCES Fuzzy= 5.719 N Dangle= 0.000 N COVERAGE BOUNDARY Xmin = 2728729.500 Xmax = 2785919.750 Ymin = 214973.594 Ymax = 237709.422 STATUS The coverage has not been Edited since the last BUILD or CLEAN. COORDINATE SYSTEM DESCRIPTION Projection STATEPLANE Zone 5376 Datum NAD27 Units FEET Spheroid CLARKE1866
i) Check the point coverage with the base map. In Arcview add the crwnstat theme to the project view. Check that the points representing the monitoring sites fall on the stream.
j) Add the site name and number to the point attribute table. In the Project Window/Tables open the point attribute table for crwnstat, Click on Table/Start Editing, then Edit/Add Field and add the desired fields. Be aware of being consistent with the titles for your table columns and the format of the data for linking the table with the water quality data tables that will be created later. I found that for site identification numbers it is best to enter this data as a string type versus number type.
name Site Number
See image of the point attribute table for the River Watch sites below:
Since there are USGS stations at the same locations as some of the River Watch stations a field for the site number of the corresponding USGS site was added to the point attribute table.
Repeat this process for the USGS and the springs sites and create separate point coverages for them. Add these themes to the project in Arcview and check there locations in relation to the map themes.
For this model I used the edwards aquifer and roads coverages which are available on the Austin CD-ROM. They were already in the correct projection for the project.
River Watch Data- The citizen water quality data, described above, was obtained from the River Watch in an Excel spreadsheet.
Edit the data and arrange it into the desired format for Arcview within Excel. The columns with the site names and site identification numbers should have the same title as the point attribute table that was created in Arcview. When other tables are produced that can be linked within Arcview the column names and data format are important for linking the tables.
Leave spaces empty in the table where the data is bad or no data exists. Create a column for <,>,and = symbols for those parameters that have measurements recorded in that way. See image below:
When the table is in the format wanted for Arcview go to File/Save As and save the file ("Save file as type") as Text (Tab Delineated). Name the file name.txt. In this form the table can be directly imported into Arcview. Move the file into the project directory. In Arcview go to Project/Add Table and an "Add Table" window will open. Under "List Files as Type" go to Delineated Text (*.txt). Add the name.txt file and check the point attribute table that appears in the project. See image below: (note: This method is for the water quality data or the flow data, but not both at the same time)
USGS Data- Internet Table
The USGS water quality data and flow data are arranged in tables in text format, as described above. The following method is one way to get from the text format on the internet to a DAT table in Arcview. The goal is to create a table in Excel like the River Watch and then import it into Arcview, as described above.
1) Download the USGS table from the internet as a text file into a directory.
2) Open the file in Microsoft Word and format the text in courier font, size 8 which will fit the data on the page and align the columns (landscape page alignment would work also). Save the file in text format, name.txt. (not name.doc)
3) Go to Excel and open the text file. The "Text Import Wizard" will take you through a series of windows for importing the data:
Check the Excel spreadsheet to make sure the water quality data was delineated into the columns correctly. The other text and flow data can be deleted. It is at this point that the weighted flow calculations for the storm flow datat can be done as described above in the Data Section. The data can now be edited within Excel to the form desired for the Data Attribute Table in Arcview.
4) Save the file as a regular Excel file until you have finished editing the data and have it in the form you want to use in Arcview.
5) In Excel, save the file as a text file, tab delineated.
6) Transfer the file to the project directory for use in Arcview.
7) Import into Arcview in the same manner as the River Watch data was imported above.
The following are a few examples of procedures that can be done with the model that is now set up in Arcview.
1) Locating sites on the map and linking the site with the water
quality data associated with the site as shown below.
Link the tables that have data that are relevant to each other. For example (as illustrated above), link the Riverwatch point attribute table with the water quality data tables of the River Watch and USGS. With this done the user can identify a site on the map with the information pointer (with the site theme activated) and identify the site. Then, from the point attribute table the user can highlight that site. The data associated with that site will automatically be highlighted in the data tables. The data can then be used for analysis such as graphing, as shown below.
2) Graphing the data to see trends over time. See example graph below:
In Arcview, with the data table activated, click on the chart icon. From the Chart Properties window choose the fields to chart and the field to use for labeling the chart axis. Highlight the data that you desire to have in the chart.
The GIS project is an excellent tool for making the data collected by the River Watch and other entities more accessible to interested parties. GIS presents the data in a visual format that connects the data with a geographic location. GIS allows the user to see where a particular collection site is in relation to other sites and to easily view the water quality data at other sites. The data can also be accessed to be used for what ever analysis is of interest to the user. Water quality data collected by other entities can also be included creating a more complete picture of the water quality of the watershed.
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