This web site is my fall semester 1999 term project of the CEE 6930 GIS in Water Resources, Water Division, Civil and Environmental Engineering, Engineering Department, Utah State University, U.S.A. This class is the distance learning class from the class CE 394K.3 GIS in Water Resources.

Water-Surface Evaporation in Reservoir
By Vitoon Thititanapak
CEE 6930 GIS in Water Resources
December, 1999

Outline

•   Class and term paper
  
•   Background
  
•   Objective
  
•   Concept and Conceptual Map
  

• Develop the water-surface area
  
• Calculation of the evaporation in reservoir
  
• Conclusion
  
• Reference
  
• PowerPoint Presentation
  

Class and term paper

     This term paper is a part of the course CEE 6930: GIS in water resources. GIS is stand for Geographic Information System. This class is an ONLINE class for Utah State University (USU) students on the Fall Semester 1999. The classes lecture live at the University of Texas at Austin and the lectures are posted on the web site for watching after. Dr. David R. Maidment is the instructor and Dr. David G. Tarboton is the USU coordinator.   

Background

     According to Dingman in Physical Hydrology (1993), he stated that evaporation is an important factor of reservoir in determining the yield of water supply and the reservoir construction. The 62% of precipitation that falling to the land is evapotranspiration, or it is about 72,000 cubic Kilometers per year. In this amount, 3% is the evaporation from open-water surface and it is about 2,160 cubic Kilometers per year. The other 97% is the evapotranspiration that is the water evaporates from soil-surface and the plant transparency. In the reservoir operation, evaporation is one of the factors in calculating the loss of water from reservoir. Sometimes it is called "evaporation loss."

     GIS is a computer technology that can be applied to present the geospatial data or the data information in graphic features. People can better understand the data presentations in the graphic feature than in the table or the list forms. The development of computer technology is advancing very quickly and it has abilities to support the GIS concept. Nowadays GIS is used to present the information in many fields such as civil, water resources, environment, agriculture, geology, hydrology, business, city and urban planning and etc. The concept of GIS is to import the data from many sources in several forms such as maps, images, tables, pictures, and digital products, and then overlay them together to create a new graphic and do calculation to solve the interested problems. The GIS data is available from several sources such as the U.S. Department of transportation, the U.S. Census Bureau, the U.S. Geology Survey (USGS), the Environmental Protection Agency (EPA), etc. The users also can create the data by themselves. They can download some data from the World Wild Web in Internet or load files data from some recorded devices such as CD. Some data are free of charge but some have to pay for.   

Objective

My purposes for this term paper are:

1. To study the effect of evaporation upon the reservoir water-surface.
   
2. To apply GIS techniques to find the evaporation from reservoir.
   

Concept and Conceptual Maps

     The concept of this paper is using GIS data to develop the water-surface areas of the reservoir at every 1-meter storage level depth, and then calculates the evaporation loss. The annual reservoir operation plan can be produced by using the monthly mean reservoir-storage elevation to estimate the monthly evaporation losses. The short-term reservoir operation plan can be carried out by using the current reservoir storage elevation to predict the evaporation of the next month.

*Estimated monthly release demands are estimated by using the mean monthly demands data of all of the water-use activities, such as evaporation loss, seepage loss, irrigation demand, domestic-use demand, transportation demand, flood control, land improvement demand, etc.

 
The concept of the term paper processes is divided into three main sections.

• Section one, Theory Study: is to study the physics of evaporation in Hydrologic Cycle and how to measure the evaporation upon the water-surface areas of the reservoir.
  

• Section two, Data Collection: is to collect data and select the study areas.
  

• Section three, Data Development: is to import the necessary data into a GIS program to create the water-surface area of the reservoir, then calculate the volume of evaporation.
  

Data Collection and study area

     When I started to look at GIS data, first I studied from the lectures and exercise handouts. I found that my paper could due with the exercise 3: Delineating the watersheds and stream network and the exercise 6: Hydrologic Properties of the Landscape. So I knew that I needed to use DEM grid files, Rf1 shape file, dam site location, HUC shape file, evaporation file and Class-A pan coefficient. I then worked on Internet and searched for several web sites. I had to look at the large - scale map (1: 250,000) from EPA web site and USGS web site to select a study area. I looked for all necessary data I needed for the study area. Unfortunately, I could not find every data I needed. I could find DEM, Rf1, Dam site location. Therefore, I decided to use the evaporation data and Class-A pan coefficient from the NOAA Technical Report NWS 33.

     To view the study area, I looked in the web site of EPA, http://www.epa.gov/ost/BASIN/STATES/UT/ and clicked mouth at the Middle Bear basin then downloaded core data. I added dam.shp and Rf1.shp to ArcView and opened the themes. I saw the locations of the dams in the Middle Bear basin and I selected Cutler dam as my study area.

Dam Name   CUTLER
County          BOXER  ELDER  ( Box Elder County)
River              BEAR  RIVER
Dam height  109 ft.  or  33.23 m.
Longitude     - 111.950000
Latitude         41.816667
Normal Storage Elevation     + 4407 ft.  or  + 1343.60 m.
Normal Storage Capacity      13,200 Acre-ft.  or  16. 236 M. m.³ 

Data Collection

When I decided to use Cutler Dam as my study area, I collected all data from several sources.
- DEM from USGS       http://edcwww.cr.usgs.gov/doc/edchome/ndcdb/ndcdb.html

• RF1 from EPA        http://www.epa.gov/OST/BASINS/HUCS/16010202/
  
• Dam site from  EPA  http://www.epa.gov/OST/BASINS/HUCS/16010202/
  

• Pan - evaporation data from 
  

Conclusion

     The result can achieve the objectives of the term paper. I mean that the methods and the processes can be applied to solve the similar problems. The result may not complete. That is because the DEM grid file is processed after the CUTLER Dam has been constructed and already has water storage. Therefore, the contours below the water surface can not be developed. It is assumed that the water level in the reservoir of the CUTLER DAM is at the same level every month. The evaporation from the water-surface of the CUTLER DAM is about 9.717 Million cubic meters per year. The area of the water-surface at elevation + 1343.60 m. is about 9.6 square kilometers.
 
     The method using in this paper should be developed in the step of TARDEM. TARDEM should be able to work with ArcView directly without the needs of MS-DOS processing.

     I think that, this method can be applied to find the inundated areas at the interested elevation for estimating the reservoir area in the feasibility study of a new dam project.

     The future work that I want to do is to complete my objectives of this paper. I think when the dam was designed, the water-surface areas at every water levels of the reservoir were measured and usually were plot as a Water-Surface versus Elevation Curve. I want to use this data to create the water-surface area in ArcView to solve the DEM data problem as I mention above.
   

• Reference
  

-   POWER POINT PRESENTATION