I I I GALE I I I FOUNDRY POND DIAGNOSTIC/FEASIBILITY STUDY I FINAL REPORT I JANUARY 1992 I I Prepared For: The Town of Hingham -' And The Massachusetts Division of Hater Pollution Control I Clean Lakes Program In Association With I M.G.L. Ch. 628 I Massachusetts Clean Lakes Program I Prepared By: GALE ASSOCIATES, INC. I Eight School Street Weymouth, MA 02189 and I K-V ASSOCIATES, INC. 281 Main Street I Falmouth, MA 02540 I I B°ston • St. Augustine • Baltimore I I I FOUNDRY POND I DIAGNOSTIC/FEASIBILITY STUDY I FINAL REPORT TABLE OF CONTENTS I SECTION ' PAGE • List of Figures iii List of Tables v " Executive Summary , vii • 1.0 INTRODUCTION 1 1 -1 Background 1 • 1.2 Scope of Work and Study Objectives 5 2 . 0 DIAGNOSTIC EVALUATION 7 I 2.1 Recreational Use and Public Access 7 I 2.2 Watershed Description . 10 2. 3 Watershed Land Uses 17 • 2.4 Watershed Geology 24 2 . 5 Basin Morphometry 31 | 2.6 Hydrologic Budget 34 M 2.7 Phosphorus and Nitrogen Budgets 39 • 2.8 Limnological Data 43 • 2.9 Tributary Water Quality 67 2 .10 Macrophyton. 74 | 2.11 Fisheries 78 2.12 Inventory of On-Site Wastewater Disposal 82 1 Practices i 2.13 Lake Sediment Characteristics 82 I I I I TABLE OF CONTENTS (CONT.) I SECTION PAGE • 3.0 FEASIBILITY ASSESSMENT 90 3 .1 Watershed Management 96 I 3.2 In-lake Restoration. , , 112 3 .3 Implementation of Recommendations 130 B 3.4 Public Meeting 139 I 4 . 0 REFERENCES 140 5.0 APPENDICES • A Land Use Descriptions B Limits of Detection I C Road Salt and Groundwater Protection D Job Estimate I E Public Comments I F Environmental Notification Form I I I I I I 11 1 1 LIST OF FIGURES 1 FIGURE TITLE PAGE 1 Locus Map 2 2 Assessor * s Map 3 1 3 Public Access to Foundry Pond 8 4 Area of Critical Environmental Concern 11 5 Surface Watershed 13 6 Watershed Subdrainage Basins 14 7 Open Space Land in Hingham 16 1• 8 Watershed Land Use Map 18 9 USGS Map ...... 26 10 Availability of Groundwater in Unconsolidated Deposits 27 1 lOa Major Soil Types , 30 11 Bathymetric Map 33 12 Components of the Foundry Pond Hydrologic Budget 38 1 13 Limnological Sampling Stations 44 14 Foundry Pond Inflow 49 15 Annual Fluctuation in Total Phosphorus at Foundry Pond Inlet and Outlet 65 16 Seasonal Trends in Nitrogen Concentration at Foundry Pond Outlet 68 1 17 Seasonal Trends in Nitrogen Concentration at Foundry Pond Inlet 69 19 18 Tributary Sampling Stations 71 19 Density of Aquatic Macrophytes •1 in Foundry Pond 75 20 Species Distribution of Aquatic Macrophytes in Foundry Pond 77 1 iii I I I I LIST OF FIGURES I FIGURE TITLE PAGE 21 Soft Sediment Thickness Map 85 I 22 Sediment Sampling Stations 87 23 Graph of Phosphorus Monthly Load I Compared to River Flow 94 24 Zoning Map of Hingham Flood Plain I and Watershed Protection District 99 25 Location of Structures for Weir River Diversion and Foundry Pond Drawdown 125 I 26 Sketch of the Foundry Pond Dam 126 27 Proposed Grading Plan for Sediment I Removal in Foundry Pond 129 28 Milestone Schedule for the I Restoration of Foundry Pond 135 29 Tributary Water Quality Monitoring I Program Sampling Stations 138 I I I I I I I IV 1 1 1 LIST OF TABLES 1 TABLE TITLE PAGE 1 Percent Land Use Types within the 1w Foundry Pond Watershed 19 2 Foundry Pond Morphometric and Watershed measurements 32 1 3 Foundry Pond Hydrologic Budget 36 • 4 Foundry Pond Phosphorus Budget 40 5 In— lake Limnological Data 46 6 Inlet/Outlet Limnological Data 47 1 7 Foundry Pond Phytoplankton •V Composition and Abundance • 55 i 8 Foundry Pond Phytoplankton Abundance Summary 59 9 Total Nitrogen/Total Phosphorus in Foundry Pond 63 10 Weir River Water Quality Survey 70 11 72 12 Species Composition 80 |13 Septic Survey 83 14 Sediment Characteristic 88 15 Great Lakes Sediment Rating Criteria 89 16 Recommended Management Program 1 91 • Costs and Benefits . 17 Annual Phosphorus Loads From Land Use H Activities in the Foundry Pond Watershed . 93 I I I V I I I LIST OF TABLES I TABLE TITLE PAGE 18 Summary of Impacts, Permits and Funding Sources for Recommended Management 1 Alternatives 132 • 19 Potential Funding Sources 133 i I i i f i i i i i i i i i VI Executive Summary The recreational, aesthetic, and fisheries and wildlife habitat values of Foundry Pond have been reduced as a result of infilling from historical dredging activities in the pond and upstream in the Weir River. Colonization of the southern portion of the pond basin by an emergent marsh has reduced the open water area available for boating and fisheries by 33% and contributed to degraded water quality conditions. Thus, a year-round water quality survey of the pond and its tributaries was conducted with funds provided by the Town of Hingham and the Massachusetts Clean Lakes Program. The physical, chemical and biological characteristics of the pond were assessed, as were the physical, hydrogeological and land use characteristics of the watershed. These data were used to determine the sources of the nutrients which are causing the pond's water quality degradation and to develop a plan for in-lake restoration and watershed management. Every lake has a limited capacity (carrying capacity) to assimilate the nutrients which it receives without expressing the undesirable conditions of nuisance algal and aquatic plant growth which are associated with cultural eutrophication. Water quality data collected during the year-round study of Foundry Pond and its tributaries indicate that phosphorus inputs from the Weir River, which transports 99.9% of the annual phosphorus load to the pond, are more than twice as high as the pond's carrying capacity. This excessive phosphorus loading, in conjuction with the shallowness of the pond basin from historical sediment deposition, have caused eutrophic water quality conditions to occur in the pond. Recommendations for the restoration of Foundry Pond consist of a reduction in phosphorus inputs to tributaries from wastewater disposal systems and stormwater runoff, as well as implementing in- lake restoration measures for reducing phosphorus recycling by aquatic plants. Thus, both in-lake and watershed phosphorus reduction measures will be necessary in order to improve the pond's water quality to a level which will reduce the amount of aquatic plant growth which currently exists. In summary, watershed management plan recommendations include: (1) phosphorus load reductions to tributaries from stormwater runoff by maximizing its infiltration, in conjunction with increased roadway and catch basin cleaning, and no phosphorus fertilizer applications; and Boston • St. Augustine * Baltimore vii I --^^ 1 GALE I I <2) phosphorus load reductions to tributaries from wastewater by upgrading failed wastewater disposal systems located I within 300 feet of tributaries and ponds. The latter recommendation involves the implementation of a public education program to teach watershed residents about reducing I phosphorus loading to tributaries from septic systems and lawns, as well as the adoption and amendments of Zoning and Board of Health bylaws which protect surface and groundwater quality within the I watershed. Impoundment water level manipulation to maximize detention times is also recommended. I The recommended in-lake restoration plan involves the use of sediment removal to: increase open water area available for boating and fisheries, reduce aquatic plant biomass and internal nutrient recycling, increase in-lake circulation and to improve the I recreational fishery. Due to the fact that the major source of phosphorus contributing to I the increased aquatic plant growth is from in-lake sediment, restoration measures should be phased. Initially public education should be stressed. Then, in-lake measures should be undertaken. Finally, if further reduction in phosphorus input becomes I necessary, construction of upstream holding basins should be undertaken. I I I I I I I Boston * St. Augustine , . • Baltimore | Vlll I I I 1.0 INTRODUCTION I 1.1 Background Foundry Pond is a small (1.58 hectares, 3.8 acres), shallow I impoundment which is located on the Weir River, between Weir Street and Kilby Street, in Hingham, Massachusetts (Figure 1). I The pond was created during the late 1700 *s when the existing earth and masonry dam was erected near the mouth of the Weir River for use in operating an iron foundry. This and a second I iron foundry built by Benjamin Thomas were both destroyed by fires which occurred in 1828 and 1876. A wool scouring plant, I built on the same site by Colonel Weston, also burned in 1888. During this time the name of the pond changed from Thomas' to I Weston's Pond (Town of Hingham, 1893). As indicated on Sheet 53 of the Hingham Assessor's Map (Figure 2), a fish ladder was I constructed at this time in order to facilitate the passage of herring into the pond during their spring spawning run. The Old Colony Railroad, which operated between 1849 and 1957, I built the bridge which crosses the Weir River at the pond I inlet (John Richardson, personal communication). During the first half of the 20th Century, ice was extracted I from the pond and sold commercially by the Nantasket Ice Company. Foundry Pond first served a recreational function I when it was owned by the Hingham Sportsmen's Club, (circa 1950) which rebuilt the fishway along the northeast side of the dam then donated the pond and abutting land to the I Conservation Commission in 1961. I I I I I I GALE I I I I I I I I I I I I I SCALE : 1 cm = 25O m FIGURE 1 LOCUS PLAN I FOUNDRY POND I H1NGHAM, MASSACHUSETTS I I Boston Baltimore I I I The pond reportedly began infilling following dredging of the Weir River (circa 1954-1956}, which occurred in an upstream I direction, between Foundry Pond and Main Street.