EPA Region III Case Studies
JACK’S CREEK /SITKIN SMELTING AND REFINERY
Wetland Remediation / Restoration / Vernal Pool Creation
Encompassing 105 acres, the Jacks Creek site is located in the village of Maitland in a rural farming area of Mifflin County, Pennsylvania. The site is a former smelting and precious metals reclamation facility, with Sitkin Smelting Company operating at the site from 1958 until 1977. Currently, a portion of the site property is used for a metal scrap yard and an aluminum recycling facility. Residential and agricultural land uses surround the site with Jacks Creek forming the northwest property boundary.
A complex assortment of buildings, waste piles, and large areas of soils were contaminated. Soils contained high levels of lead, copper, zinc, cadmium, and PCBs. Floodplain wetlands on the site were contaminated with runoff from the waste piles and upland soils.
The sediments of Jacks Creek near the site contained similar contaminants as the soils. A consumption advisory based on PCB contamination was issued for multiple fish species by the Pennsylvania Department of Health for Jacks Creek adjacent to and down stream of the site.
EPA’s selected remedy for soils included contaminant stabilization, on-site consolidation, and capping of the waste piles and soils. The clean up numbers for lead at the site were 1000 ppm for the active industrial area, 200 ppm for the floodplain soils, and 110 ppm for sediments in the tributaries and creek. The floodplain remediation required the removal of vegetation in a segment of the riparian corridor of the creek.
As residual contamination in floodplain soils exceeded the sediment remediation criterion, it was imperative to restore the floodplain using techniques that would reduce stormwater sheet flow to the creek and prevent soil migration. Because soil excavation activities impacted the existing wetlands on site, wetlands needed to be recreated in the riparian corridor along Jacks Creek in accordance with regulations (CERCLA §121(d); NCP) and applicable or relevant and appropriate requirements (ARARs: 25 Pa. Code 105.17, 105.20a, 105.46 and 105.46(a)).
- Restore riparian corridor
- Recreate floodplain wetlands
- Reduce stormwater flow to the creek
- Prevent residual contamination from migrating
- Grade the area with clean soil to create vernal pools within the floodplain
- Plant potted trees and shrubs throughout the remediated floodplain
- Use live stakes along the banks of the tributaries and creek
- Seed with a mixture of herbaceous annuals and perennials to provide rapid soil stabilization and short term habitat while woody plants grow
- Eliminate invasive species that will overwhelm native plantings
- Monitor to ensure success of wetland and stream bank restoration
Vernal pools - Following soil excavation, the floodplain was graded using uncontaminated off site soils. While the plan called for two interconnected pools, the final topography resulted in 8 depressions varying in size and depth. The more shallow pools are likely to become completely filled with sediment over time. The remaining pools are deep enough to accommodate sediment and still retain water seasonally. Coarse woody debris that was stock-piled during the remediation phase was placed in the pools to provide additional habitat for the invertebrate and vertebrate community. Leaves from the intact riparian corridor will be placed in each pool each fall until the planted trees and shrubs are large enough to provide sufficient leaf litter.
Vegetation - To stabilize the soil and to restore the vegetative community, a wet meadow seed mix with clover and annual rye was planted over the entire remediated floodplain. This mixture provided enough diversity in plant requirements to address wet to dry conditions over the entire remediated area. Sapling trees and shrubs similar in composition to the surrounding riparian forest were planted within the remediated area with emphasis on the perimeter of each vernal pool. Live stakes were installed along Jacks Creek and the onsite tributaries.
The objective of the monitoring plan for the Jacks Creek site is to document the effectiveness of the ecological enhancement in successfully creating functioning vernal pools, stormwater control, and riparian corridor restoration. Monitoring of these parameters will take place each year during early spring and early fall.
- Water depth
- Surface area of pool
- Water temperature
- Dissolved oxygen
- Wetland characteristics
- Depth of sediment
- Depth of leaf litter
- Woody plant stem counts
- Percent ground cover by herbaceous plants
- Aquatic invertebrates