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10_GW_Monitoring Plan
Memorandum
To: Jeffrey Colby
From: Karilyn Heisen, PE, D.WRE
Date: July 22, 2022
Subject: Buck Island Groundwater Monitoring Plan
Recharge capacity at the Buck Island site is dependent on annual and seasonal changes in water
level and the ability of the adjacent surface water bodies to transport flow which discharges
through the groundwater. Model simulations indicate that average annual recharge capacity at the
site is 1.2 MGD with monthly ranges from 0.99 to 1.5 MGD.
Pressure transducers should be installed in the 9 groundwater wells in Table 1 to measure water
levels during the initial 3 months of system operations. Monthly groundwater levels should be
taken following system start-up. Well screens are assumed to be in the shallow subsurface
bracketing or just below the water table. Well depths will be verified as part of initial groundwater
monitoring.
Water level measurements should be taken at the six locations listed in Table 1 and shown on
Figure 1. Stage-discharge curves should be developed for all 7 locations. Continuous water level
data should be collected at SW-10A, SW-12 and SW-2 during the initial 3 months of system
operations. Weekly water levels should be collected at the other three locations during the initial 3
months. Monthly groundwater levels should be taken following system start-up.
Prior to system start-up the stream channels and road crossing should be surveyed and evaluated
to assess the capacity of culvert and water level control structures to maintain water levels and
transport the increased surface water flows.
Water quality samples will be collected and analyzed quarterly at wells BW-218 (upgradient), BW-
225 (down-gradient), BW-231 (down-gradient), and surface water locations SW-3 (Plashes Brook
upstream), SW-2 (Plashes Brook downstream), SW-9A (Big Sandy Bog upstream), SW-10A (Big
Sandy Bog), and SW-12 (cranberry bog downstream). Water quality samples will be analyzed as
shown in Table 2.
Buck Island Groundwater Monitoring Plan
July 22, 2022
Page 2
10_GW_Monitoring Plan
Table 1 – Groundwater and Surface Water Monitoring Points
Well Location Water Level
Monitoring
Water Quality
Sampling
BW-218 Upgradient Yes Yes
MW-17 Upgradient (near Plashes Brook) Yes
MW-22A Upgradient Yes
BW-225 Downgradient (west towards
cranberry bog)
Yes Yes
MW-8 Cross-gradient (across cranberry
bog)
Yes
BW-231 Downgradient (east towards
Plashes Brook
Yes Yes
MW-23A Cross-gradient (across Plashes
Brook)
Yes
MW-24 Downgradient (south) Yes
MW-25 Downgradient (south) Yes
SW-9A Big Sandy Bog Upstream of Inlet Yes Yes
SW-10A Big Sandy Bog Upstream of
Control
Yes Yes
SW-10B Big Sandy Bog Downstream of
Control
Yes
SW-12 Outlet Brook of Bogs Yes Yes
SW-3 Plashes Brook Upstream Yes Yes
SW-13 Plashes Brook Yes
SW-2 Plashes Brook Upstream of Sluice Yes Yes
Table 2 Water Quality Monitoring Plan Parameters and Frequency
Parameter Frequency of Analysis
Specific Conductance Quarterly
pH Quarterly
Nitrate-Nitrogen (NO3) Quarterly
Total Nitrogen (NO3+NO2+TKN) Quarterly
Total Phosphorus Quarterly
Volatile Organic Compounds Annually (groundwater samples only)
Buck Island Groundwater Monitoring Plan
July 22, 2022
Page 3
10_GW_Monitoring Plan
Figure 1 – Groundwater and Surface Water Monitoring Points