Evaluation of Hydrologic Models for Alternative Covers at Mine Waste Sites

EPA Grant Number: R829515C007
Subproject: this is subproject number 007 , established and managed by the Center Director under grant R829515
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: HSRC - Rocky Mountain Regional Hazardous Substance Research Center for Remediation of Mine Waste Sites
Center Director: Shackelford, Charles D.
Title: Evaluation of Hydrologic Models for Alternative Covers at Mine Waste Sites
Investigators: Shackelford, Charles D. , Benson, Craig H.
Institution: Colorado State University , University of Wisconsin - Madison
EPA Project Officer: Lasat, Mitch
Project Period: October 1, 2002 through September 30, 2005
Project Amount: Refer to main center abstract for funding details.
RFA: Hazardous Substance Research Centers - HSRC (2001) RFA Text |  Recipients Lists
Research Category: Hazardous Waste/Remediation , Land and Waste Management

Objective:

The conventional approach to final cover design is to use a compacted clay layer and/or a geomembrane (polymeric sheet) as the primary barrier to flow. This approach is impractical at many mine sites because of expense, the lack of suitable clay borrow sources, and the potential for damage by frost and desiccation. As a result, alternative approaches to final cover design are being investigated. Although the underlying principle of alternative covers (e.g., monolithic covers, capillary barrier covers) is simple, predicting their hydrologic performance is fraught with difficulties that introduce appreciable uncertainty regarding the accuracy of predictions, and only limited effort has been devoted towards ensuring that predictions made with hydrologic models accurately represent field conditions. Comprehensive studies have not yet been conducted because hydrologic data from full-scale instrumented alternative covers have only become available within the last two years. The proposed research will represent the first comprehensive evaluation of five different hydrologic models (HELP, UNSAT-H, Vadose/W, Hydrus-2D, and LEACHM) commonly used for the design of cover systems based on high quality field data from large-scale test facilities of alternative covers that have been constructed and monitored at 12 sites in the US.

The proposed study has four objectives: (1) a baseline assessment and comparison of the algorithms in existing hydrologic models when applied to a variety of meteorological conditions, (2) an unbiased critical assessment of the predictive capabilities of existing hydrologic models for covers using field data, (3) improvement of the hydrologic model (or models) that have the most promise so that predictions made with the model are accurate, and (4) incorporation of additional algorithms in the model that can be used to assess the impact of long-term processes such as plant secession, pedogenesis, and climatic change.

Approach:

The first objective will be achieved by performing comparative simulations with each hydrologic model to define differences in output obtained from the five models for different types of alternative covers and different locations with different climatic conditions. The second objective will be achieved by performing simulations using a subset of the five models based on the results of the first objective for each test facility using data representative of field conditions as input. The third objective will be achieved by modifying the algorithms with deficiencies that were identified in the first two objectives to accurately reflect field behavior based on the detailed and comprehensive data collected at the field sites. This effort may require substantial re-writing of portions of the codes and incorporation of additional algorithms. The fourth objective will involve adding algorithms to the model (or models) for simulating long-term effects that may influence the hydrologic behavior of covers. The characteristics of these algorithms will be based on the short-term pedogenetic and vegetative changes observed at the field sites, as well as the knowledge that has been gained from natural analog studies.

Expected Results:

The key deliverable from this study will be an improved, easy-to-use, and field-verified model for long-term assessment of alternative covers at a variety of sites and climatic conditions. This study will also leverage Rocky Mountain Regional HSRC funds by making use of extensive investments that have been made by three federal agencies (USEPA, USDOE, and US Army).

Supplemental Keywords:

RFA, Industry Sectors, Scientific Discipline, Air, INTERNATIONAL COOPERATION, ENVIRONMENTAL MANAGEMENT, Waste, TREATMENT/CONTROL, Ecosystem Protection/Environmental Exposure & Risk, Waste Treatment, Remediation, Ecosystem/Assessment/Indicators, climate change, Restoration, Mining - NAIC 21, Air Pollution Effects, Ecological Effects - Environmental Exposure & Risk, Hazardous Waste, Environmental Monitoring, Ecological Risk Assessment, Geology, Groundwater remediation, Hazardous, Environmental Engineering, Atmosphere, Risk Assessment, hydrogeology, monitoring, aquatic ecosystem, contaminated waste sites, contaminant transport, contaminated sites, acid mine drainage, remediation technologies, bioavailability, groundwater hydrology models, restoration strategies, mining, hydrology, leaching of toxic metals, alternative covers, treatment, ecological recovery, geochemistry, contaminated groundwater, acid mine discharge, aquatic ecosystems, environmental rehabilitation, water quality, contaminated aquifers, mining waste, extraction of metals, aquatic toxicology, ecological indicators, heavy metal contamination, heavy metals, mining wastes, stream ecosystem, acid mine runoff, groundwater pollution

Progress and Final Reports:

  • 2003 Progress Report
  • 2004 Progress Report
  • Final

  • Main Center Abstract and Reports:

    R829515    HSRC - Rocky Mountain Regional Hazardous Substance Research Center for Remediation of Mine Waste Sites

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R829515C001 Redox Transformations, Complexation and Soil/Sediment Interactions of Inorganic Forms of As and Se in Aquatic Environments: Effects of Natural Organic Matter
    R829515C002 Fate and Transport of Metals and Sediment in Surface Water
    R829515C003 Metal Removal Capabilities of Passive Bioreactor Systems: Effects of Organic Matter and Microbial Population Dynamics
    R829515C004 Evaluating Recovery of Stream Ecosystems from Mining Pollution: Integrating Biochemical, Population, Community and Ecosystem Indicators
    R829515C005 Rocky Mountain Regional Hazardous Substance Research Center Training and Technology Transfer Program
    R829515C006 Technical Outreach Services for Communities and Technical Assistance to Brownfields
    R829515C007 Evaluation of Hydrologic Models for Alternative Covers at Mine Waste Sites
    R829515C008 Microbial Reduction of Uranium in Mine Leachate by Fermentative and Iron-Reducing Bacteria
    R829515C009 Development and Characterization of Microbial Inocula for High-Performance Passive Treatment of Acid Mine Drainage
    R829515C010 Reactive Transport Modeling of Metal Removal From Anaerobic Biozones
    R829515C011 Assessment of Electrokinetic Injection of Amendments for Remediation of Acid Mine Drainage
    R829515C012 Metal Toxicity Thresholds for Important Reclamation Plant Species of the Rocky Mountains
    R829515C013 An Improved Method for Establishing Water Quality Criteria for Mining Impacted Streams