Alternative Landfill Cover Project Profiles:
Monolithic ET Cover at Lopez Canyon Sanitary Landfill, CA
Monolithic ET Cover at Lopez Canyon Sanitary Landfill, CA
Last Updated: October 7, 2003
Site Information
Site Name, Location:
Lopez Canyon Sanitary Landfill, Los Angeles, CA USA
(EPA Region 9)
Site Type:
MSW landfill
Superfund Site:
No
Federal Facility:
No
Bottom liner:
No
Annual Precipitation:
17 in
Project Information
Project Name:
Monolithic ET Cover at Lopez Canyon Sanitary Landfill, CA
Project Scale:
Full scale
Demonstration Program:
Not a demonstration project
Project Status:
Installed
Date Installed:
1999
Project Description/ Purpose:
The purpose of this project is to demonstrate performance of the ET cover compared to a conventional cover and validate theoretical water balance analyses. The cover was conditionally approved in 1998 and received final approval in October 2002 following analysis of field performance data.
Regulatory Status:
Approved
Monitoring System:
Two moisture monitoring systems were installed, one at Disposal Area A and one at Disposal Area ABplus in May and November 1999, respectively. Each monitoring system has two stacks of time domain reflectometry probes, which measure soil moisture at 24-inch intervals to a maximum depth of 78 inches, and a station for collecting weather data.
Cover Information
Cover Type:
Monolithic Evapotranspiration
Design of Cover:
3-foot silty sand/clayey sand layer, which overlies a 2-foot foundation layer
Types of Vegetation:
Native vegetation including artemesia, salvia, lupines, sugar bush, poppy, and grasses.
Cover Installation:
The cover soil was placed in 18-inch lifts and compacted to 95% with a permeability of less than 3x10-5 cm/s.
Drainage Layer:
No
Biointrusion Layer:
No
Gas Collection Layer:
No
Water Balance Model:
UNSAT-H
Modeling Results:
UNSAT-H was calibrated with 12 months of soil moisture content and weather data. Following calibration, UNSAT-H predicted a cumulative percolation of 50 cm for the ET cover and 95 cm for a conventional cover over a 10-year period. The model predicted an annual percolation of approximately 0 cm for both covers during the first year. During years 3 through 10 of the simulation, the model predicted less annual percolation for the ET cover than for the conventional cover.
Designer Name:
GeoSyntec Consultants
Performance Data Available:
Yes
Summary and Description of Performance Data:
Based on nearly 3 years of data, there is generally less than a 5 percent change in the relative volumetric moisture content at the bottom of the cover compared to nearly 90 percent change near the surface. This implies that most of the water infiltrating the cover is being removed via evapotranspiration and is not reaching the bottom of the cover.
Maintenance Activities:
During the first 18 months, irrigation was conducted to help establish the vegetation. Once or twice a year, brush is cleared to comply with Fire Department regulations. Prior to the rainy season, an inspection is conducted to check and clear debris basins and deck inlets. No mowing activities or fertilizer applications have been conducted or are planned.
Summary and Description of Costs:
Costs were estimated at $4.5 million, which includes soil importation, revegetation, quality control and assurance, construction management, and installation and operation of moisture monitoring systems.
Comments:
In 1998, the landfill received conditional approval for a monolithic ET cover, which required a minimum of 2 years of field performance data to validate the flow model used for the design. An analysis was conducted and provided the basis for final approval in October 2002 by the California Regional Water Quality Control Board - Los Angeles Region.
Point(s) of Contact
Primary Contact
Role in Project:
Organization:
GeoSyntec Consultants
Name:
Tarik Hadj-Hamou
Address:
2100 Main Street, Suite 150, Huntington Beach, CA 92648
Email from Doug Walters, City of Los Angeles Bureau of Sanitation, to Kelly Madalinski, EPA. September 25, 2003.
Hadj-Hamou, T. and Kavazanjian, E., Jr. 2003. "Monitoring and Evaluation of Evapotranspirative Cover Performance," Sardinia 2003 - 9th International Waste Management and Landfill Symposium, Cagliari, Italy, October.
