Management and Effects of Coalbed Methane Produced Water in the Western United States (2010) / Chapter Skim
Currently Skimming:
5 Environmental Effects of Coalbed Methane Development and Produced Water Management
5 Environmental Effects of Coalbed Methane Development and Produced Water Management
Pages 113-160
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 113... ...
This chapter is weighted toward discussion about the Powder River Basin because large volumes of CBM produced water are discharged to surface waters or impoundments or are being put to beneficial use there, relative to other western CBM basins. Correspondingly, most of the scientific literature on the environmental effects of CBM produced water and most of the controversy that has precipitated litigation or media attention about CBM produced water management has originated from research conducted in this basin.
|
From page 114... ...
. In contrast, depths to methane-bearing coalbeds in the Powder River Basin are relatively shallow and less consolidated than those of the other western CBM basins (see Chapter 2)
|
From page 115... ...
in support of this monitoring program. In Wyoming, in response to concerns about potential effects to groundwater from CBM development in the Powder River Basin, BLM established a regional groundwater monitoring program that is outlined as part of the Wyodak CBM Final Environmental Impact Statement (BLM, 1999)
|
From page 116... ...
gradients resulting from several years of pumping. wyoming In the Wyoming portion of the Powder River Basin, the Wyoming State Geological Survey, in collaboration with BLM, analyzed data from 111 wells in the BLM deep-well monitoring network, collected from 1993 to 2006 (Clarey, 2009)
|
From page 117... ...
. Since 1997, hydrological impacts in the Powder River Basin from CBM development have been regionally confined to some of the Tongue River Member coals of the Fort Union Formation and some of the sandstone beds in the overlying Wasatch Formation.
|
From page 118... ...
Data from the Powder River Basin suggest that some of the CBM aquifer water there is also likely at least thousands of years old in aquifers with limited connectivity (see Chapter 2)
|
From page 119... ...
. In 2008, 64 percent of the CBM produced water in the Wyoming portion of the Powder River Basin was managed in surface impoundments (see Box 4.1)
|
From page 120... ...
and the length of time these impacts may persist following closure, the Wyoming DEQ Water Quality Division recently completed a comprehensive review of five years of groundwater monitoring data associated with CBM produced water impoundments (on- and off-channel) and their effects on shallow groundwater in the Powder River Basin.
|
From page 121... ...
, the trend analyses indicated that CBM water from impoundments resulted in no apparent water quality trend (stable trend) as a result of interaction with the underlying soils.
|
From page 122... ...
Groundwater monitoring networks established for coalbeds in the Powder River Basin in Montana and Wyoming have measured the degree to which CBM production has affected water levels in coalbed aquifers, either in proximity to areas of CBM development or near the fringes of the coalbed outcrops. Measured drawdowns ranged between 20 and 625 feet below prepumping levels.
|
From page 123... ...
About 83 percent of the impoundments in the Powder River Basin of Wyoming are onchannel and about 6 percent are unlined and off-channel, with intent to recharge groundwater beneath impoundments. The remaining impoundments are lined and off-channel, with the aim to reduce or prevent leakage and infiltration of CBM produced water into underlying shallow alluvial groundwater.
|
From page 124... ...
. SURFACE WATER Discharges of CBM produced water to surface water and/or impoundments can affect the receiving water quality, whether perennial streams or rivers, ephemeral drainages, or surface impoundments.
|
From page 125... ...
. Perennial streams and rivers The concentration of CBM operations in the Powder River Basin and differences in regulation between Wyoming and Montana have generated a number of studies that have examined the potential effects of CBM produced water discharges on the Powder River and Tongue River drainages in Wyoming and Montana.
|
From page 126... ...
ALL Consulting (2008) used specific conductance and SAR data to evaluate changes in water quality and streamflow for five watersheds in the Powder River Basin with CBM development and produced water discharge.
|
From page 127... ...
in streams and rivers receiving CBM produced water discharges in the Powder River Basin. Ammonium, at concentrations in the range of 1 to 3 mg/L, is frequently present in CBM produced water at the wellhead.
|
From page 128... ...
found that the δ13CDIC for produced water samples collected from different coal zones and from different parts of the Powder River Basin were enriched in δ13CDIC, ranging from +12 per mil to +22 per mil as a result of the biogenic production of methane, which preferentially removes 12C. In contrast, water samples not influenced by CBM produced water typically have negative δ13CDIC values.
|
From page 129... ...
ePhemeral drainages and imPoundments Several studies have documented increases in concentrations of TDS, sodium, and trace elements and the pH of CBM produced water that is discharged to ephemeral drainages in the Powder River Basin. Recalling that the outfall which discharges CBM produced water into an impoundment usually represents a combination of CBM product water combined from several CBM wells (see Chapter 4)
|
From page 130... ...
(2006) examined the chemistry of trace elements in CBM discharge water reacting with semiarid ephemeral stream channels in the Powder River Basin.
|
From page 131... ...
One study showed a statistically significant increase in flow-adjusted SAR values in the Powder River after CBM development began around 1990, but all other studies of the Tongue and Powder rivers that the committee was able to access found that inputs from traditional oil and gas operations and the effects of droughts made the influence of CBM development on water quality difficult to discern. This difficulty persisted even when adjustments were made in the data analyses to account for wet and dry periods.
|
From page 132... ...
TABLE 5.1 Comparison of Mean Concentrations of Constituents Measured in Water Samples from Multiple Impoundments Within Five Watersheds of the Powder River Basin, 2003–2005, with Relevant Water Quality Standards Overall Mean for Range in Mean Federal Federal Chronic/ Agriculture Livestock Samples from Surface Values Measured Drinking Acute Clean Standards Standards Impoundments in 5 Within Impoundments Water Water Act Aquatic (Wyoming (Wyoming Analyte Units PRB Watershedsa in 5 PRB Watershedsa Standardb Life Criterionc Class II) d Class III)
|
From page 133... ...
d Wyoming DEQ (2005)
|
From page 134... ...
A study of discharge water quality and the quality of water in receiving impoundments in five watersheds of the Powder River Basin showed a general increase in concentrations of trace elements from outfall to disposal impoundments. Stream depletion studies have involved only theoretical modeling, conducted for the Piceance, Raton, Northern San Juan, and Sand Wash basins in Colorado.
|
From page 135... ...
Application of CBM produced water from the Powder River Basin over multiple years increased soil electrical conductivity (EC) and SAR to depths of 30 centimeters.
|
From page 136... ...
(2008) examined the effects of irrigation with CBM produced water on soils and plants of the Powder River Basin by comparing soil and plant conditions following various irrigation practices with those from nonirrigated sites.
|
From page 137... ...
After use of CBM produced water ceases, additional soil management, including soil amendments,11 may be required to restore soil agricultural resources to pre-CBM water application conditions. Much of the actual practice of applying CBM produced water to landscapes is limited to industry's efforts -- largely on industry-owned land or land for which the industry has paid a rental or lease fee -- and application of CBM produced water to landscapes or for irrigation is not a widespread practice at present.
|
From page 138... ...
. Details of existing laboratory studies on the effects of TDS, of interactions between elevated TDS and other stressors, of sodium bicarbonate on organisms, and of field studies on the effects of CBM produced water on organisms are outlined in subsequent sections.
|
From page 139... ...
Salt Creek is a headwaters tributary of the Powder River. Salt Creek was primarily impacted by traditional oil and gas development at the time of the study with produced water, therefore, of different composition than CBM produced water.
|
From page 140... ...
Based on these models and assumptions of direct exposure of study species to undiluted CBM produced water, produced waters from many CBM sites within the study area in the Powder River Basin could be toxic to aquatic organisms. For example, employing the Mount et al.
|
From page 141... ...
; calculations completed as part of this study. magnesium, chlorine, and sulfate found in CBM produced water from the Wasatch and Fort Union formations from the eastern Powder River Basin in Wyoming.
|
From page 142... ...
. As shown in Table 5.2, the 50th and 75th percentile concentrations of bicarbonate from groundwater samples collected from the Powder River Basin were 712 mg/L and 1,103 mg/L, respectively.
|
From page 143... ...
. For comparison to bicarbonate values in CBM produced water and the Powder River (Table 5.1)
|
From page 144... ...
field assessments of cBm Produced water effects A comprehensive assessment of the potential impacts of CBM discharges on aquatic communities is currently being conducted by the USGS and the Powder River Aquatic Task Group (ATG) , a consortium of state, federal, and nongovernmental organizations (Peterson et al., 2009; Farag et al., 2010)
|
From page 145... ...
proposed that CBM produced water discharges could destroy vegetation in stream channels, increase erosion and deposition of sediment in streams and reservoirs, and degrade water quality. Consequently, algae, aquatic invertebrates, fish, amphibians, and other biological
|
From page 146... ...
Coulees and ephemeral channels receiving produced water in the Powder River Basin had greater percentages of nonnative plant species than did similar coulees and ephemeral channels not receiving produced water. Stearns et al.
|
From page 147... ...
The committee's calculations using simple published models to predict water quality toxicity to fish and invertebrates using major ions also indicate that undiluted CBM produced water from many sites within the Powder River Basin could be toxic to many aquatic organisms. Importantly, these results are based on mean concentrations and discharges and on direct and prolonged exposure to undiluted, untreated CBM produced water or its constituents on conventional laboratory test species.
|
From page 148... ...
Studies of this nature are also complex to conduct and interpret because of the interactions and overlap between habitats, water quality, limited length of time to complete studies involving community transitions that might occur over extended periods of time, and species migration. A comprehensive assessment is currently being conducted by a consortium of state, federal, and nongovernmental organizations to establish current conditions for habitat and aquatic communities for the Powder River Basin.
|
From page 149... ...
A cursory review of the complaints indicated numerous complaints related to water quantity and water quality impacts to private domestic water supply wells. These problems were generally attributed by the complainant to poor practices by the operator (e.g., improperly cased wells)
|
From page 150... ...
However, no legal requirement exists for collection of baseline water quality or water level data.18 One registered complaint from the Powder River Basin in Wyoming cited increased erosion from unmanaged CBM produced water discharge (see Figure 5.6)
|
From page 151... ...
Much of the information on effects derives from the Powder River Basin of Wyoming, where over 90 percent
|
From page 152... ...
The EPA is conducting a broader analysis of the potential effects on groundwater quality and public health from hydraulic fracturing throughout the entire oil and gas industry. A primary mode for disposal of CBM produced water, especially in the Powder River Basin of Wyoming and somewhat in the Colorado portion of the Raton Basin, is in surface impoundments.
|
From page 153... ...
Specific conductance and SAR of water resources may not be the most meaningful diagnostic or representative measures of CBM produced water influence on receiving water bodies, particularly in the Powder River Basin. Isotope analyses may provide more representative characterization of the influence of CBM produced water on groundwater and surface water.
|
From page 154... ...
at the site of discharge. Testing these laboratory results against field studies and with species relevant to the study areas in the Powder River Basin has not yet been completed and would be a valuable contribution to determine the potential effects of CBM produced water on organisms.
|
From page 155... ...
. A comprehensive assessment is currently being conducted to establish current conditions for habitat and aquatic communities for the Powder River Basin in order to measure and monitor future changes.
|
From page 156... ...
2002. Water quality and environmental isotopic analyses of ground-water samples collected from the Wasatch and Fort Union formations in areas of coalbed methane development: Implications to recharge and ground-water flow, eastern Powder River Basin, Wyoming.
|
From page 157... ...
2008. Strontium isotopes as indicators of aquifer communication in an area of coal bed natural gas production, Powder River Basin, Wyoming and Montana.
|
From page 158... ...
2010. Innovative approaches for tracing water co-produced with coalbed natural gas: Applications of strontium and carbon isotopes of produced water in the Powder River Basin, Wyoming and Montana.
|
From page 159... ...
2007. Organic com pounds in produced waters from coalbed natural gas wells in the Powder River Basin, Wyoming.
|
From page 160... ...
2005. 2004 Annual Coalbed Methane Regional Ground-water Monitoring Report: Montana Portion of the Powder River Basin.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.