By Ted Auch, Great Lakes Program Coordinator, and Elliott Kurtz, GIS Intern
The Great Lakes may see a major increase in the number of sand mines developed in the name of fracking. What impacts has the area already seen, and does future development mean for the region’s ecosystem and land use?
Sand is a necessary component of today’s oil and gas extraction industry for use in propping open the cracks that fracking creates. Silica sand is a highly sought after proppant for this purpose and often found in Wisconsin and Michigan. At the present time here in Ohio our Utica laterals are averaging 4,300-5,000 tons of silica sand or “proppant” with demand increasing by 85+ tons per lateral per quarter.
Wisconsin’s 125+ silica sand mines and processing facilities are spread out across 15,739 square miles of the state’s West Central region, adjacent to the Minnesota border in the Northern Mississippi Valley. These mines have dramatically altered the landscape while generating proppant for the shale gas industry; approximately 2.5 million tons of sand are extracted per mine. The length of the average shale gas lateral well grows by > 50 feet per quarter, so we expect silica sand usage will grow from 5,500 tons to > 8,000 tons per lateral. To meet this increase in demand, additional mines are being proposed near the Great Lakes.
Migration of the sand industry from the Southwest to the Great Lakes in search of this silica sand has had a large impact on regional ecosystem productivity and watershed resilience. The land in the Great Lakes region is more productive, from a soil and biomass perspective; much of the Southwest sandstone geology is dominated by scrublands that have accrue plant biomass at much slower rates, while the Great Lakes host productive forests and agricultural land. Great Lakes ecosystems produce 1.92 times more soil organic matter and 1.46 times more perennial biomass than Southwestern ecosystems.
Effects on the Great Lakes
Quantifying what the landscape looks like now will serve as a baseline for understanding how the silica sand industry will have altered the overall landscape, much like Appalachia is doing today in the aftermath of strip-mining and Mountaintop Removal Mining. West Central Wisconsin (WCW) has a chance to learn from the admittedly short-cited and myopic mistakes of their brethren across the coalfields of Appalachia.
Herein we aim to present numbers speaking to the diversity and distribution of WCW’s “working landscape” across eight types of land-cover. We will then present numbers speaking to how the silica mining industry has altered the region to date and what these numbers mean for reclamation. The folks at UC Berkeley’s Department of Environmental Science, Policy , and Management describe “Working Landscapes” as follows:
a broad term that expresses the goal of fostering landscapes where production of market goods and ecosystem services is mutually reinforcing. It means working with people as partners to create landscapes and ecosystems that benefit humanity and the planet… A goal is finding management and policy synergies—practices and policies that enhance production of multiple ecosystem services as well as goods for the market…Collaborative management processes can help discover synergies and create better decisions and policy. Incentives can help private landowners support management that benefits society.
We used the 1993 WISCLAND satellite imagery to determine how WCW’s landscape is partitioned and then we applied these data to an updated inventory of silica sand mine boundaries to determine what existed within their boundaries prior to mining. The point locations of Wisconsin’s current inventory of silica sand mines was determined using the “Geocode Address” function in ArcMap 10.2 using the Composite_US Address Locator. Addresses were drawn from mine inventory information originally maintained by the West Central WI Regional Planning Commission (WCWRPC) and now managed by the WI Department of Natural Resources’ Mines, pits and quarries division. Meanwhile current mine extent boundary polygons were determined using one of three satellite data-sets:
- 2013 imagery from the USDA National Agriculture Imagery Program (NAIP),
- 2014 ArcMap 10.2 World Imagery, and
- 2014 Google Satellite.
What We Found
Land Cover Types Replaced by Silica Sand Mining
Thirty-nine percent of the WCW landscape is currently allocated to forests, 43% to agriculture broadly speaking, and 13% is occupied by various types of wetlands. Open waters occupy 2.6% of the landscape with tertiary uses including barren lands (1.3%), golf courses (0.03%), high and low-density urban areas (0.9%), and miscellaneous shrublands (0.6%) (See Figure 1).
Effects by Land Cover Type
Figure 2. The wood in these forests has a current stumpage value of $253-936 million and by way of photosynthesis accumulates 63 to 131 million tons of CO2 and has accumulated 4.8-9.8 billion tons of CO2 if we assumed that on average forests in this region are 65-85 years old. Putting a finer point on WCW forest cover and associated quantifiables is difficult because most of these tracts (2.7 million acres) fall within a catchall category called “Mixed Forest”. Pine (2.3% of the region), Aspen (4.7%), and Oak (3.8%) most of the remaining 1.2 million forested acres with much less sugar (Acer saccharum) and soft (Acer rubrum) maple acreage than we expected scattered in a horseshoe fashion across the Northeastern portion of the study area.
Figure 3. Seven different agricultural land-uses occupy 4.3 million WCW acres with forage crops and grasslands constituting 29% of the region followed by 1.4 million acres of row crops and miscellaneous agricultural activities. Additionally, 2% of WI’s 19,700 cranberry bog acres are within the study area generating $4.02 million worth of cranberries per year. The larger agricultural categories generate $3.2 billion worth of commodities.
Figure 4. Nearly 16% of WCW is characterized by open waters or various types of wetlands with a total area of 2,396 square miles clustered primarily in two Northeast and one Southeast segment. Open waters occupy 398 square miles with forested wetlands – possibly vernal pool-type systems – amounting to 5.4% of the region or 841 square miles. Lowland shrub and emergent/wet meadows occupy 540 and 618 square miles, respectively.
Figure 5. Of the nine types of wetlands present in this region the forested broad-leaved deciduous and emergent/wet meadow variety constitute the largest fraction of the region at 1,107 square miles (7.1% of region). Some percentage of the former would likely be defined by Wisconsin DNR as vernal pools, which do the following according to their Ephemeral Pond program. The WI DNR doesn’t include silica sand mining in its list of 14 threats to vernal pools or potential conservation actions, however.
These ponds are depressions with impeded drainage (usually in forest landscapes), that hold water for a period of time following snowmelt and spring rains but typically dry out by mid-summer…They flourish with productivity during their brief existence and provide critical breeding habitat for certain invertebrates, as well as for many amphibians such as wood frogs and salamanders. They also provide feeding, resting and breeding habitat for songbirds and a source of food for many mammals. Ephemeral ponds contribute in many ways to the biodiversity of a woodlot, forest stand and the larger landscape…they all broadly fit into a community context by the following attributes: their placement in woodlands, isolation, small size, hydrology, length of time they hold water, and composition of the biological community (lacking fish as permanent predators).
Figure 6. Broad-leaved evergreen lowland shrub wetlands constitute ≈2.1% of the region or 319 square miles with most occurring around the Legacy Boggs silica mines and several cranberry operations turned silica mines in Jackson County. Meanwhile broad-leaved deciduous and needle-leaved lowland shrub wetlands are largely outside the current extent of silica sand mining in the region occupying 1.9% of the region with 293 square miles spread out within the northeastern 1/5th of the study area.
Figure 7. Finally, miscellaneous land-covers include 200 square miles of barren land, 145 square miles of low/high intensity urban areas including the cities of Eau Claire (Pop. 67,545) and Stevens Point (Pop. 26,670) as well as towns like Marshfield, Wisconsin Rapids, Merrill, and Rib Mountain-Weston. WCW also hosts 3,204 acres (0.03% of region) worth of golf courses which amounts to roughly 21 courses assuming the average course is 157 acres. Shrublands broadly defined occur throughout 0.6% of the region scattered throughout the southeast corner and north-central sixth of the region, with the both amalgamations poised to experience significant replacement or alteration as they are adjacent to two large silica mine groupings.
Producing Mine Land-Use/Land-Cover Change
To date we have established the current extent of land-use/land-cover change associated with 25 producing silica mines occupying 12 square miles of WCW. These mines have displaced 3 square miles of forests and 7 square miles of agricultural land-cover. These forested tracts accumulated 31,446-64,610 tons of CO2 per year or 2.4-4.9 million tons over the average lifespan of a typical Wisconsin forest. These values equate to the emissions of 144,401-295,956 Wisconsinites or 2.5-5.1% of the state’s population. The annual wood that was once generated on these parcels would have had a market value of $126,097-197,084 per year. Meanwhile the above agricultural lands would be generating roughly $1.5-3.3 million in commodities if they had not been displaced.
However, putting aside measurable market valuations it turns out the most concerning result of this analysis is that these mines have displaces 871 acres of wetlands which equals 11% of all mined lands. This alteration includes 158 acres of formerly forested wetlands, 352 acres of lowland shrub wetlands, and 361 acres of emergent/wet meadows. As we mentioned previously, the chance that these wetlands will be reconstituted to support their original plant and animal assemblages is doubtful.
We know that the St. Peter Sandstone formation is the primary target of the silica sand industry with respect to providing proppant for the shale gas industry. We also know that this formation extend across seven states and approximately 8,884 square miles, with all 91 square miles overlain by wetlands in Wisconsin. To this end carbon-rich grasslands soils or Mollisols, which we discussed earlier, sit atop 36% of the St. Peter Sandstone and given that these soils are alread endangered from past agricultural practices as well as current O&G exploration this is just another example of how soils stand to be dramatically altered by the full extent of the North American Hydrocarbon Industrial Complex. The following IFs would undoubtedly have a dramatic effect on the ability of the ecosystems overlying the St. Peter Sandstone to capture and store CO2 to the extent that they are today not to mention dramatically alter the landscape’s ability to capture, store, and purify precipitation inputs.
- IF silica sand mining continues at the rate it is on currently
- IF reclamation continues to result in “very poor stand of grass with some woody plants of very poor quality and little value on the whole for wildlife. Some areas may be reclaimed as crop land, however it is our opinion that substantial inputs such as commercial fertilizer as well as irrigation will be required in most if not all cases in order to produce an average crop.”
- IF the highly productive temperate forests described above are not reassembled on similar acreage to their extent prior to mining and reclamation is largely to the very poor stands of grass mentione above
- For example: Great Lakes forests like the ones sitting atop the St. Peter Sandstone capture 20.9 tons of CO2 per acre per year Vs their likely grass/scrublands replacement which capture 10.6-12.8 tons of CO2 per acre per year… You do the math!
- “None two sites are capable of supporting the growing of food. They grow trees and some cover grass, but that is all. General scientific research says that the reclaimed soils lose up to 75% of their agricultural productivity.”
Quote from a concerned citizen:
I often wonder what it was like before the boom, before fortunes were built on castles of sand and resultant moonscapes stretched as far as the eye could see. In the past few years alone, the nickname the “Silica Sand Capital of the World” has become a curse rather than a blessing for the citizens of LaSalle County, Illinois. Here, the frac sand industry continues to proliferate and threaten thewellbeing of our people and rural ecosystem.
References & Resources
- The US Forest Service defined Watershed Resilience as “Over time, all watersheds experience a variety of disturbance events such as fires and floods [and mining]. Resilient watersheds have the ability to recover promptly from such events and even be renewed by them. Much as treating forests can make them more resilient to wildfire, watershed restoration projects can improve watershed resilience to both natural and human disturbances.”
- Great example: Virginia Tech’s Powell River Project