Remedial Action Plan - Rochford Field - Newhall Remediation Project

More documents

Recommendations

Info

Fill was encountered beneath the entire site and adjacent parcels, including Mill Rock Park, the Sewer Pump Station (addressed in a separate RAP) and the former Hamden Middle School. At Rochford Field, the thickest fill deposits were encountered in a northwest-southeast trending zone roughly similar to the path of the former stream observed in the historic aerial photographs. Fill appears to pinch out to the north towards Mill Rock Road. Fill was encountered in borings along the Newhall Street right of way. Fill from Rochford appears to extend southerly and may be contiguous with the fill encountered by others in the block south of Newbury Street. Additionally, although explorations could not be located in the center of Winchester Avenue, due to the presence of utilities, based on comparisons of fill thicknesses on either side of the street; it appears that the fill deposited on Rochford Field is contiguous with that deposited in Mill Rock Park. Natural overburden sediments underlying the fill consist of organic material and stream (alluvial) sediments overlying glaciodeltaic deposits composed of interbedded layers of primarily silt and sand sized particles. Regionally, the glaciodeltaic sediments have been mapped as thick (up to 300 ft thick in the site vicinity) glacial Lake Connecticut deposits that extend from Lake Whitney to Long Island Sound. The deposits reportedly pinch out to the east (Prospect Hill) and north (Mill Rock). The glaciodeltaic deposits encountered in Rochford Field explorations appeared to decrease in thickness towards the east. Alluvial and former wetland sediments were encountered above the glaciodeltaic deposits and ranged in thickness from 1.5 to 8 ft. The former wetland and stream sediments reflect the nature of the site prior to filling. Thicker alluvial sediments generally reflect areas where fill was deposited in wetlands or standing water bodies. Refer to Appendix B for geologic cross-sections of the study area 2.1.2 Hydrogeology In 2005, CTDEEP reclassified groundwater beneath the southern portion of Rochford Field as “GB”, indicating that the resource is not intended for use as a public water supply without prior treatment. Groundwater in abutting areas to the west and southwest of the site had historically been classified as “GB.” Groundwater in the northern portion of Rochford Field remains a “GAA” resource (see Figure 2A). Private or public wells have not been identified in the site area. The majority of the shallow groundwater beneath the site is generally flowing in a westerly/southwesterly direction. Groundwater flow beneath Rochford Field is primarily to the southwest, towards the Hamden Community Center. Flow beneath the northwestern corner of the field, however, appears to be northwesterly, towards a surface water stream on the west side of Newhall Street (Figure 2B). Haley & Aldrich encountered groundwater at depths ranging from 7 to 10 ft below grade in Rochford Field. Groundwater elevations encountered during the supplemental Phase III investigation were noted to be slightly higher than those detected in the Phase II/III explorations, likely reflecting seasonal variations in water levels. The water table in the northern and southern portions of Rochford Field was generally found at the top of the natural alluvial or glaciodeltaic sediments. The water table in the central portion of Rochford Field was encountered within the fill deposits; this area marks the location of former standing water bodies and a stream, filled in the 1920s and 1930s. Based on an evaluation of the shallow 7
groundwater flow patterns and observations from the exploration program, significant impacts to groundwater flow from on-site or adjacent utilities were not observed. Groundwater elevations were based on two sets of measurements performed by Haley & Aldrich and others in November 2004 and February 2005. Piezometric contours are shown on Figure 2B and were previously included in the 2005 Supplemental Phase III report. The location of subsurface utilities in and immediately adjacent to the subject site is shown in Figure 2B. Based on an evaluation of the flow patterns and observations from the exploration program, significant impacts to groundwater flow from on-site or adjacent utilities were not observed. 2.1.3 History For a more detailed description of the history of Rochford Field, please refer to the Phase I ESA. The following is a brief summary: Based on a review of aerial photographs, historic maps and Town of Hamden Annual Reports, the former wetland area east of Newhall Street, south of Mill Rock Road and north of Newbury Street (now Rochford Field) was used as a “dump” in the 1920s and early 1930s. According to information on file in the Hamden Tax Assessors office and information in the 1936 Hamden Annual Report, the Town of Hamden acquired the property from John M. Morse and Dorothy H. Morse Struck on 28 September 1936. According to interviews with former residents, much of the area between Morse Street and Mill Rock Road, west of Winchester Avenue and east of Newhall Street was used as an industrial landfill and depository for “coke fill” (charcoal residue and ash). In late 1936 and 1937, the area was graded, topped with approximately 6 inches of loam and turned into a recreation field. A ¼-mile long cinder running track was constructed on the field in 1938. Rochford Field was officially dedicated on 7 June 1939. In the 1940s, a field house and fence were added. In 1989, the tornado that passed through Hamden caused a significant amount of damage in Rochford Field. Apparently, trees were uprooted exposing ash and cinder fill as well as other solid waste materials. The Town contracted for the renovation of Rochford Field in 1992. Haley & Aldrich reviewed a memorandum to the Contractor hired by the Town that cautioned against mixing “cinders and furnace slag material” when stripping topsoil from the field. According to the memorandum, the materials had been used as a running surface for “an old running track that looped the fields”. In April 2001, CTDEEP and Town officials temporarily closed Rochford Field based on results of environmental testing in 2000 and 2001 which detected metals and SVOCs in shallow soils above RSR criteria. In July 2001, M&E monitored interim remedial actions, including the placement of asphalt pavement or concrete on several unvegetated, high traffic areas at Rochford Field. The areas that were paved included: locations near the entrance gate, around the dugout areas, under the bleachers and adjacent to the water fountain. M&E reportedly encountered “old batteries” during remedial efforts for the southern dugout area. M&E also supervised the placement of sod in the area of sprinkler lines and the placement of grass seed in 8
Page 1 and 2: REMEDIAL ACTION PLAN ROCHFORD FIELD
Page 3 and 4: TABLE OF CONTENTS LIST OF TABLES LI
Page 5 and 6: LIST OF TABLES Table No. Ia Ib IIa
Page 7 and 8: The 4.84 acre Rochford Field is a l
Page 9 and 10: levels of VOCs; cyanide was detecte
Page 11: 2. CONCEPTUAL SITE MODEL 2.1 Genera
Page 15 and 16: presence of the oil scrap metal cor
Page 17 and 18: On-site soil washing Bioremediation
Page 19 and 20: 3.4 CTDEEP Selected Remedy In 2005,
Page 21 and 22: The depth of the liner and gravel w
Page 23 and 24: The impermeable barrier will be slo
Page 25 and 26: 5. LONG-TERM GROUNDWATER MONITORING
Page 27 and 28: TABLE Ia SUMMARY OF ANALYTICAL RESU
Page 49 and 50: TABLE Ib SUMMARY OF ANALYTICAL RESU
Page 63 and 64:
TABLE Ib SUMMARY OF ANALYTICAL RESU
Page 65 and 66:
Page 67 and 68:
Page 69 and 70:
TABLE IIa SUMMARY OF ANALYTICAL DAT
Page 71 and 72:
Page 73 and 74:
Page 75 and 76:
Page 77 and 78:
Page 79 and 80:
Page 81 and 82:
Page 83 and 84:
Page 85 and 86:
Page 87 and 88:
TABLE IIb SUMMARY OF ANALYTICAL DAT
Page 89 and 90:
Page 91 and 92:
Page 93:
Page 161 and 162:
APPENDIX B Selected Figures from Pr
Page 163 and 164:
NEWHALL ROCHFORD FIELD WINCHESTER A
Page 165 and 166:
BLAKE CIRCLE MILL ROCK ROAD MIDDLE
Page 167 and 168:
TABLE X Page 1 of 3 SUMMARY OF CONC
Page 169 and 170:
TABLE X Page 3 of 3 SUMMARY OF CONC
show all

Remedial Action Plan - Rochford Field - Newhall Remediation Project

Create successful ePaper yourself

Delete template?

Save as template?