BulkTransmission/Water Quality

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Transmission Water Quality

Water Quality
Present, Potentially Affected

Three federal statutes impact water quality at a geothermal site. They are:

  • The Clean Water Act(CWA) (33 U.S.C. 1251-1387) sets standards for the chemical, physical and biological properties of all bodies of water in the United States. It mandates a permitting system and is responsible for programs to mitigate the impacts of certain pollutants.
  • The Oil Pollution Act (OPA) (33 U.S.C. 2701) sets prevention, preparedness, and emergency response plan requirements to ensure environmental qualities.
  • The Safe Drinking Water Act(SDWA)(42 U.S.C. 300 et. seq.) protects public drinking water sources from unsafe pollutant levels by setting water quality standards. This act requires programs to ensure aquifer, reservoir, river, and lake health.

http://teeic.indianaffairs.gov/er/transmission/legal/index.htm

Both primary and secondary water quality standards are mandated at the state and federal levels. Primary standards are strict requirements to mitigate public health effects. Secondary standards are strong recommendations, but are not required. These recommendations include cosmetic and aesthetic properties such as color, odor, and taste.

Water from geothermal sites are subsequently used as:

  • Drinking water to go onto a public water treatment plant
  • Untreated ground water and surface water
  • Treated effluent
  • Reclaimed or recycled water

These water sources are governed by state and federal regulations. Whether or not the injection water is potable, is decided on the state level. Potable water quality varies state to state, however, it is commonly referred to water that can be consumed by humans without posing any health risks.

https://www.epa.gov/uic/aquifer-recharge-and-aquifer-storage-and-recovery#impact_usdw

Water Quality Impacts & Mitigation

Construction, pesticides and herbicides, and site erosion can cause a range of water quality impacts. Runoff from chemicals and sedimentation can cause groundwater seepage into aquifers and affect drinking water. Surface runoff may also impact riparian species in or near streams, lakes, and wetlands. Chemicals and sedimentation disrupt natural plant processes and can make wildlife and fish sick.

Spill Prevention

  • Develop a Spill Prevention, Countermeasure, and Control Plan
  • Prevent solid matter contaminants, debris, and hazardous liquid spillage into waterways, lakes, land, and underground aquifers.
  • Contaminants can be found in refuse, garbage, cement, concrete, sanitary waste, industrial waste, oil, aggregate processing tailing, and mineral salts.
  • Avoid storing, transferring, or mixing of oils, fuels, or other hazardous materials where accidental spills could enter surface or groundwater.
  • Equip on site structures and vehicles with spill clean up kits.

Contamination Procedures

  • If pre-existing contamination is present, suspend work until the contamination type is identified and a clean up method is proposed.
  • If a spill is beyond the on-site’s equipment and personnel capability, contact Emergency Services.
  • If spills occur in standing water, use floating booms, skimmer pumps, and holding tanks to recover and contain materials.
  • Use oil-absorbent materials, tarps, and storage drums to contain and control any minor releases of transformer oil.
  • In the event that excess water and liquid concrete escapes from foundations during pouring, direct the spillage to bermed areas adjacent to the borings where the water would infiltrate or evaporate and the concrete would remain and begin to set. Before materials dry, remove and transport to an approved landfill for disposal.
  • Dispose construction wastewater used for concrete batching to on-site retention basins equip with zero discharge capabilities. After the water has evaporated, remove concrete residue and dispose off-site.

Construction

  • Avoid stockpiling or disposing excavated construction materials, such as drilling fluids or mud near or on stream banks and lake shorelines, unless protected from high water or storm runoff.
  • Manage excess concrete to avoid stockpiling and construction site expansion.
  • To minimize sediment, install culverts on access roads to account for low-flow conditions in the dry season.
  • Wash vehicle wheels to reduce sediment transfer from gravel to paved roads.
  • To avoid chemical and construction material runoff, place staging areas away from wetlands or stream buffers.
  • Construct culverts in non-fish bearing streams to reduce water quality habitat impacts.
  • Construct raised tower footing or enclosed flood control dike foundations to reduce sediment runoff.
  • Avoid tower placement in active drainage channels to mitigate mud and debris flow in the event of high precipitation or a flood.
  • Prior to construction and excavation, identify existing underground gas, electric, sewage, water, fuel, and telephone lines to mitigate groundwater seepage or unnecessary flow in the event that lines are ruptured.
  • Place synthetic liners beneath spoiled material piles mitigate aquifer contamination.
  • Bury hazardous waste pipelines in accordance with federal and state regulations to reduce damage from railroad infrastructure, landowners digging, and the pressure from bodies of water. In some cases where consolidated rock is present, pipelines may be buried at a shallower depth.
  • Corrosion is the leading factor in pipeline failures, therefore, install cathodic protection systems along the pipelines to strengthen and protect it from corrosion. Cathodic protection systems offset soil and moisture corrosion potential by facilitating a current through the pipeline.
  • Routinely inspect pipelines to confirm proper operating conditions and to check for corrosion.
  • Before clearing and grading begins, use straw wattles, water bars, covers, silt fences, and restrict sensitive area access.

Refueling

  • Conduct vehicle, heavy machinery fueling procedures and maintenance at approved staging and construction yards. Store fuel tank and truck storage away from any water source, dry or flowing.

Stormwater Pollution Prevention Plan (SWPP)

  • Develop these plans to educate and train employees on evacuation drills, how to operate heavy equipment, spill emergency procedures, and proper chemical storage and use. Acquiring these skills has the potential to decrease spill incidences and emergency response time.
  • Design the plan to address activities adjacent to or encroaching upon water sources including streams, lakes, or wetlands.

Herbicides and Pesticides

  • Apply these chemicals away from water sources and follow the minimum dose indicated on the label.

Sediment trapping devices

  • If towers or substations are located in an active drainage channel, use dikes to divert runoff.
  • Avoid using hydraulically controlled culverts, as they inhibit aquatic organism passage.
  • Avoid constructing the culvert slope to exceed the stream’s gradient.
  • Partially bury the culvert in the streambed to maximize sediment retention.
  • Use certified weed-free straw bale barriers to control sediment in runoff waters. Only use straw bale barriers where sediment-laden water can pond, to allow the sediment to settle out.
  • Use rock, gravel bags, sandbags, or fiber rolls to act as dams across a constructed swale or drainage ditch to reduce water velocity. This allows the sediment to settle and reducing erosion.
  • Below the work site, place padding in streambeds to trap sediment from the construction site. Remove padding upon project completion.