Alternative Landfill Cover Project Profiles:
Monolithic ET Cover at U.S. Marine Corps Air and Ground Combat Center (MCAGCC) at Twentynine Palms, CA
Monolithic ET Cover at U.S. Marine Corps Air and Ground Combat Center (MCAGCC) at Twentynine Palms, CA
Last Updated: May 20, 2003
Site Information
Site Name, Location:
U.S. Marine Corps Air and Ground Combat Center (MCAGCC) at Twentynine Palms, Twentynine Palms, CA USA
(EPA Region 9)
Site Type:
MSW landfill
Superfund Site:
No
Federal Facility:
Yes
Bottom liner:
No
Climate:
Very hot summers and warm winters typical of the southern California upland desert environment. Most precipitation comes primarily as rain, which 45% of the average annual precipitation coming July through September as summer thunderstorms. Very hot summers with low relative humidity result in high values of potential evapotranspiration (PET). PET values for the summer months are much higher than precipitation, which results in low actual values of ET.
Annual Precipitation:
4 in
Project Information
Project Name:
Monolithic ET Cover at U.S. Marine Corps Air and Ground Combat Center (MCAGCC) at Twentynine Palms, CA
Project Scale:
Demonstration
Demonstration Program:
Alternate Cover Assessment Program (ACAP)
Project Status:
Installed
Date Installed:
1997
Project Description/ Purpose:
The purpose of this project is to evaluate the field-scale performance of a monolithic ET cover design. This project was included in the first phase of the ACAP.
Monitoring System:
Lysimeter (5.8m x 16.1m) composed of 40-mil HDPE geomembrane and collection pipe at the down-slope end of the lysimeter collect infiltrated water, which is conveyed to a collection tank. Segmented time domain reflectometry probes used to monitor soil moisture were arranged in three clusters. Each cluster has a shallow probe that monitors the upper 30 inches of the cover and a deeper probe that monitors 24-72 inches below the surface of the cover. One probe cluster is located in each location: within the lysimeter perimeter, outside the lysimeter perimeter, and on the embankment slope.
Cover Information
Cover Type:
Monolithic Evapotranspiration
Cover Size:
1,670 m2
Design of Cover:
73 inches of poorly graded sand with silt
Cover Installation:
Test cover was constructed on daily cover that was graded and proof-rolled prior to cover construction. Full-size construction equipment was used. Lift thickness did not exceed 6 inches (except the first lift was 24 inches to protect the membrane layer). Some water was added to aid compaction with passing loaded scrapers, dump trucks, and a dozer over the fill.
Drainage Layer:
No
Biointrusion Layer:
No
Gas Collection Layer:
No
Water Balance Model:
HELP
Modeling Results:
Predicted that local soils (poorly graded sand and poorly graded sand with silt) may prove sufficient in limiting infiltration because of the low annual precipitation and high values of PET
Performance Data Available:
Yes
Summary and Description of Performance Data:
After 14 months of field monitoring, no infiltration was collected by the lysimeter. Increases in soil moisture have been noted to a depth of 12 inches.
Comments:
Approximately 70m of the cover length is located on the upper landfill platform with the other 21m extending down the eastern slope to allow for simulation of expected surface flows.
Point(s) of Contact
Primary Contact
Role in Project:
Organization:
US Marine Corps Air and Ground Combat Center (MCAGCC)
Name:
Clay Longson, Officer-in-Charge of Construction
Address:
Facilities Management Division-Engineering Branch, Building 1130, MCAGCC P.O. Box 788106, Twentynine Palms, CA 92278-8106
Phone:
760-830-7689
Reference(s)
Gee, Glendon W., and others. 1998. Alternative Cover Assessment Project Phase I Report. December. http://www.acap.dri.edu
