# Presentation: 777025

## Hydrologic Issues in Mountaintop Mining Areas

**Ronald Evaldi, USGS-WSC, Charleston, WV**
**Daniel Evans, USGS-WSC, Louisville, KY**
**Hugh Bevans, USGS-WSC, Charleston, WV**

## “The bitterest environmental debate in the state’s history”– Sunday Gazette-Mail, Sept. 22, 2002

**“****The bitterest environmental debate in the state’s history”–**** ****Sunday Gazette-Mail, Sept. 22, 2002**

**10% of US coal is produced from Central Appalachian coalfield surface mines, mostly by mountaintop mining**
**>91,000 acres of valley fills in WV, KY, VA, and TN**
**1999 Federal court settlement required regulatory agencies to prepare an EIS on mountaintop mining, including effects on water resources**

**Notes:**
title- this is an issue that has been constantly in the news since about 1995, when US News and World Report ran a cover story on mountaintop removal.  There have been two major federal lawsuits, and there are a couple of pending class-action civil cases pending that allege that mountaintop removal increased flooding from a series of storms last year.

This is a big issue.  The method is used in southern West Virginia, eastern Kentucky, and southwest Virginia to mine almost a tenth of the coal mined in the United States.  There are several thin seams of coal pretty close together, and there’s a wide area where they’re within a few hundred feet of the surface.  Most of them are too thin to mine any other way.  Because the coal is high in energy and low in sulfur, coal companies can make money mining these seams even though they need to buy very expensive equipment and literally move mountains to get to the coal.  The mine in the background is one of the biggest in the state, the Samples mine, and is drained by some of the streams we’ve studied.  This mine covers more than three square miles, and within a five mile radius, about a third of the land has been mined.

## EIS Notes on Loss of Headwater Streams

- Intermittent and ephemeral headwater streams are largely responsible for maintaining water quality, quantity, & sediment control.
- Headwaters serve as a major area of nutrient transformation and retention, and when removed, downstream biological communities are affected for considerable distances.

## Court Ruling—Placement of valley-fill material only in ephemeral streams, and not within 100 ft of intermittent and perennial streams.

**Notes:**
Areas relate to ephemeral, intermittent, and perennial flows
Upstream from origin of intermittent flow = 14.5 acres
Upstream from origin of perennial flows = 40.8 acres
Average permitted fill = 12.0 acres, Max = 480 acres

## Median drainage area of 14.5 acres for 34 origin sites of intermittent streamflow.
Ranged from 6.3 to 45.3 acres
Medians for 2000 and 2001 varied by 3.4 acres
Median drainage area of 40.8 acres for 20 origin sites of perennial streamflow.
Ranged from 10.4 to 150 acres
Medians for 2000 and 2001 varied by 18.0 acres

- Ranged from 6.3 to 45.3 acres
- Medians for 2000 and 2001 varied by 3.4 acres
- Median drainage area of 40.8 acres for 20 origin sites of perennial streamflow.
- Ranged from 10.4 to 150 acres
- Medians for 2000 and 2001 varied by 18.0 acres

**Results**

## Comparison of Stream Characteristics

**Notes:**
Increased small particle sizes in streams downstream from valley fills. No change in cross-section geometries probably because too little time for stream to reach equilibrium since mining. 90-percent flow duration 6-7 times greater downstream from valley fills. Water temperatures fluctuate less daily and seasonally downstream from valley fills.

## Results

- Stream-bed materials below valley fills had smaller median particle sizes than below mined sites without valley fills and below unmined sites.
- Stream-water temperature below a valley fill exhibited less daily and seasonal variation than below an unmined basin.
- The 90-% streamflow duration values (streamflow exceeded 90% of the time) below valley fills were 6 to 7 times greater than below unmined basins
- Unmined basin outflow was 59% base flow, mined basin outflow was 84% base flow.

## Streamflow Comparisons

**Notes:**
At >1 in per hour mined runoff greater than unmined
At <1 in per hour unmined peak runoff greater than mined
Mined site showed double peak – overland runoff conveyed through drainage structures, compacted soils, no interception of trees and leaf litter

Increased flows from mined area resulting from decrease in evapotranspiration 

## Ballard Fork stream and rain gage network

**Notes:**
There are three stream gages and four rain gages in the network.  There’s a gage on a stream immediately downstream from a valley fill, a gage on a stream that hasn’t been mined, and a gage on the main stem.  The unmined part of the watershed is uninhabited, and mostly forest.  It does have some gas pipelines and roads on steep slopes, and judging by the gullying on them, they affect runoff- but they’re pretty representative of most unmined areas in southern West Virginia that I’m familiar with.

This project is producing two reports.  One discusses rainfall response and analyzed hydrographs, and the other discusses flow duration, low- and medium-flow statistics, and stream temperature.

## Mined basin had greater total flow
Unit daily mean flow was twice that of unmined basin.
Proportional difference was greatest at low flow.
Mined site flowed entire period; unmined site went dry.
Unit peak flows were greater in the mined basin for rainfall intensities >one inch per hour; but were less for rainfall intensities <one inch per hour.
Peak flows in the mined basin exceeded the 5-yr recurrence interval several times; but in the unmined basin, did not exceed bank-full stage (1.3-yr recurrence interval).

- Unit daily mean flow was twice that of unmined basin.
- Proportional difference was greatest at low flow.
- Mined site flowed entire period; unmined site went dry.
- Unit peak flows were greater in the mined basin for rainfall intensities **>**one inch per hour; but were less for rainfall intensities **<**one inch per hour.
- Peak flows in the mined basin exceeded the 5-yr recurrence interval several times; but in the unmined basin, did not exceed bank-full stage (1.3-yr recurrence interval).

**Results**

## Peak Flow Investigation

## MT65C--active surface mine, 

- MT65C--active surface mine,
- 	1 reclaimed valley fill,
- 	and 1 unreclaimed
- 	valley fill
- MT66--active surface mine 	and 2 reclaimed valley 	fills
- MT76--1 reclaimed valley
- 	fill
- USGS1, USGS2, and USGS3--no surface mining
- 	activities

## Results

- When peak discharge at unmined sites was **>**10-yr recurrence interval, unit flows were greater at sites with valley fills.
- When peak discharge at unmined sites was **<**10-yr recurrence interval, unit flows were greater at unmined sites.
- USACE model predicted peak flows increase during mining, decrease but **>**pre-mining after reclamation, and decrease to **<**pre-mining after reforestation.
- WVDEP model predicted that mountaintop mining increases peak flows 3 to 21%.

**Notes:**
In this study, Jeff ran indirects at 6 sites, 3 unmined and 3 mined.  The sites were as close together as possible, but the recurrence interval on the unmined streams ranged between about 10 years and about 25 years.  For the sites that were hit hardest, peak unit flow was greater from the mined and filled watersheds.  For the sites that were hit less hard, peak unit flow was less from the mined and filled watersheds than from the unmined watershed.

## Future Study Needs

## Long-Term Monitoring

- Monitor small basins (0.1 to 100 mi2) to provide data for defining background conditions, permitting mining, and assessing changes during mining, reclamation, and reforestation.
- Precipitation and atmospheric deposition
- Streamflow
- Water temperature
- Water chemistry
- Sediment
- Fluvial geomorphology
- Aquatic ecology

## Streamflow models to predict changes in flow during mining, reclamation, and reforestation.
Aquatic ecology studies to evaluate changes in aquatic communities related to changes in stream energy budgets, water temperatures, flow regimes, and habitats. 
Ground-water flow studies to determine recharge, movement, and discharge of ground water.
Water budget studies to assess impacts on the availability of water resources.
Hydrologic setting evaluations for post-mining land use.
Water-quality issues such as suspended sediment and selenium.

- Aquatic ecology studies to evaluate changes in aquatic communities related to changes in stream energy budgets, water temperatures, flow regimes, and habitats.
- Ground-water flow studies to determine recharge, movement, and discharge of ground water.
- Water budget studies to assess impacts on the availability of water resources.
- Hydrologic setting evaluations for post-mining land use.
- Water-quality issues such as suspended sediment and selenium.

- Studies

## Selenium

- An EPA study conducted as part of the Mountaintop Mining/Valley Fill EIS found that selenium in streams below valley fills exceeded the aquatic wildlife standard of 5 g/L.
-   These findings resulted in the listing of 9 streams on WVDEP’s 2002 Section 303(d) list of impaired streams.

## Selenium

- USFWS analyzed fish tissues collected downstream from mountaintop mining areas.
- Selenium was present in all sampled tissues.
- At several locations Se in tissues exceeded 4 mg/kg (ppm), a concentration that can result in reproductive failure and juvenile mortality.
- Se in some tissues approached 7 mg/kg, a  concentration that can result in reproductive failure in birds consuming these tissues.

## Selenium

- USGS has a large data base of Se concentrations in coal measures.
- Coal beds targeted by mountaintop mining are enriched in Se compared to coal beds both lower and higher in the geologic sequence.
- Other rocks in this sequence may also be enriched in Se.

## Slide 21

## Slide 22

## Slide 23

## R2=0.5291

- R2=0.5291

## Slide 25

## Selenium Questions

- How is Se leached from valley fills?
- Contributions of different source rocks
- Forms (selenite vs. selenate)
- Decay function?
- How does Se partition and cycle between dissolved and suspended phases and forms in streams and lakes?
- How does Se bioaccumulate through the food web?
- Is Se harming wildlife?
- Is Se a threat to humans?
- How can Se be managed or remediated?

## Questions

**Questions**