Final Report Diagnostic Feasibility Study Lake Boon
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fuel* *33oil FINAL REPORT Diagnostic/Feasibility Study LAKE BOON i Towns of Hudson/Stow, MA I I I I I I I I I I I FINAL REPORT I DIAGNOSTIC/FEASIBILITY STUDY i LAKE BOON • Hudson and Stow, Massachusetts i August 1987 Camp Dresser & McKee Inc. in association with i IEP, Inc. i i i i i i i i I TABLE OF CONTENTS I SECTION CONTENTS PAGE NO. SUMMARY I 1.0 INTRODUCTION 1-1 2.0 DIAGNOSTIC STUDY 2-1 I 2.1 General Description and Morphometry 2-1 2.1.1 Lake Boon Watershed 2-1 2.1.2 Public Access 2-2 2.1.3 Morphometry 2-5 I 2.1.4 History 2-5 2.1.5 Soils and Geology 2-9 2.1.6 Land Use 2-11 I 2.1.7 Wastewater Disposal 2-18 2.2 Limnologic Data 2-21 2.2.1 Lake Boon Water Quality 2-21 I 2.2.2 White Pond Water Quality 2-37 2.2.3 Phytoplankton 2-38 2.2.4 Aquatic Vegetation 2-42 I 2.2.5 Sediment Sampling 2-46 2.3 Hydrologic and Nutrient Budgets 2-49 2.3.1 Hydrologic Budget 2-49 I 2.3.2 Nutrient Budget 2-56 2.3.3 Trophic Status 2-61 I 3.0 FEASIBILITY STUDY 3.1 Introduction 3-1 I 3.2 Technology Identification and Screening 3-1 3.2.1 Reasons for Rejection of Alternatives 3-3 I 3.2.2 Alternatives for Further Consideration 3-6 3.3 Final Options 3-12 3.3.1 Option 1: Sewering and Dredging 3-12 3.3.2 Option 2: Weed Screens, Public Education, I and Septic System Measures 3-12 3.3.3 Option 3: Weed Harvester, Public Education and Septic System Measures 3-20 I 3.3.4 Option 4: Weed Harvesting, Limited Weed Screens, Public Education, and Septic System I Measures 3-22 I I I I I TABLE OF CONTENTS (continued) I SECTION CONTENTS PAGE NO, 3.4 Proposed Project 3-23 I 3.4.1 Description 3-23 3.4.2 Cost Estimate 3-27 3.4.3 Schedule 3-27 I 3.4.4 Public Participation 3-27 3.4.5 Monitoring Program 3-30 3.4.6 Environmental Evaluation 3-30 I 3.4.7 Recreational Plan 3-31 I APPENDIX I I I I I I I I I I I I I * LIST OF FIGURES I FIGURE NO. TITLE PAGE NO. M 1-1 Watershed Delineation 1-2 • 2-1 Sampling Stations, 1985-6 2-3 • 2-2 Public Access 2-4 2-3 Water Depth 2-6 • 2-4 Surficial Geology 2-10 2-5 Watershed Soils 2-12 | 2-6 Watershed Land Use 2-17 — 2-7 Sampling Stations 2-22 " 2-8 Phosphorus 2-30 • 2-9 Transparency 2-39 2-10 Phytoplankton 2-40 • 2-11 Aquatic Plant Distribution 2-43 2-lla Aquatic Vegetation Percent Coverage 2-45 | 2-12 Sediment Thickness 2-47 _ 2-13 Precipitation 2-52 • 2-14 Trophic State 2-63 • 3-1 Effect of Final Options on Trophic Status 3-24 i i i i i i i I LIST OF TABLES I TABLE NO. TITLE PAGE NO, I 2-1 Morphoroetric Data 2-7 2-2 Areas of Generalized Soil Types 2-13 • 2-3 Soils of the Lake Boon Watershed 2-14 2-4 Land Use 2-16 • 2-5 Lake Boon Water Quality, Summary, 2-23 m DWPC, 1979-1980 I 2-6 Aquatic Macrophyte Survey 2-44 2-7 Sediment Analysis 2-50 | 2-8 Hydrologic Budget 2-51 2-9 Year of Study Hydrologic Budget 2-55 • 2-10 Nutrient Budget 2-57 M 3-1 Technology Screening , 3-2 3-2 Second Alternative Screening 3-7 • 3-3 Cost Estimates of Final Options 3-24 3-4 Cost Estimate of Proposed Project 3-28 • 3-5 Implementation Schedule 3-29 i i i i i i i i I I SUMMARY I 1. Lake Boon is a diverse waterbody with two larger open water basins, and several shallow, vegetated basins. The lake is a well-used recreational resource for the people of Hudson and Stow, supporting a Town bathing I beach and swimming, boating, and fishing activity throughout the year. I 2. Dense growth of floating leaved and submerged aquatic plants interfere with recreation in the shallow eastern basins of the lake, and shallower areas of the second basin. The primary nuisance species is Camboba, not a I native of the area. Water milfoil is another nuisance species present, but it does not appear to have expanded since the EWPC (1981) study. I However, it has the potential to expand rapidly. I 3. Moderate to high populations of blue-green algae occur during the summer, contributing to borderline transparency problems. Dissolved oxygen is limited in deeper waters during summer stratification, but is not of I sufficient magnitude to impact fisheries or phosphorus recycling. No I problems with bacterial contamination were noted. 4. Lake Boon has a low flushing rate with limited water inflows due to the I large volume of the lake compared to the area of the watershed, and the prevalence of groundwater storage in the watershed area. I 5. The major controllable sources of phosphorus from the Lake Boon watershed is surface runoff from shoreline residential properties and nutrient I export from shoreline septic systems. The sandy character and high water I table of shoreline soils limit their function to attenuate phosphorus. 6. To address the main problem of dense aquatic vegetation and the secondary problem of reducing phosphorus in the water column, various combinations I of alternatives were developed. Four options were then evaluated in more I detail and the proposed project was then selected. I I I I I 7. The selected option includes the following components: a. One year only contracted hydroraking to provide interim relief from I nuisance aquatic vegetation. It may also have limited carryover benefits since hydroraking removes the roots of aquatic vegetation as well as upper portions. This will cost approximately $38,000. If I funded by the DEQE Clean Lakes Program at 75%, the Town's share will I be $9,500. b. The purchase of a medium sized weed harvester to be maintained and I operated by the towns of Hudson and Stow on an annual basis. This harvester will cut and remove nuisance aquatic vegetation, improving the recreational potential of Lake Boon. The weed harvester will cost I about $50,000, of which $12,500 is the Towns' share. Annual costs, which are not fundable under the Clean Lakes Program, will be I approximately $18,000. I c. The implementation of a watershed management plan to include a septic system pumping program; revisions to the Towns' by-laws on cesspool conversion; and a public education program. This portion of the I project is vital to the preservation of Lake Boon. Without it, the lake will deteriorate to a "pea soup" condition. This portion of the I project will cost $30,000 total, with $7,500 being the Towns' share. There will also be an annual cost of up to $10,000 for the first few I years of implementation. d. A 3-year monitoring program as required by the DEQE Clean Lakes I Program to determine the effectiveness of the project. This is estimated to cost about $50,000 total, of which $12,500 is the Towns' I share. 8. The total cost of the project is $168,000 including the state required I monitoring program, with the Towns' share $42,000. Annual costs will be I an additional $28,000. I I I 9. This project will not return Lake Boon to a "pristine" condition. However, without these preservation efforts, nuisance aquatic vegetation and algae blooms will increase rapidly over the next few years to a point where recreation is severely inhibited. This project should be implemented as soon as possible if the lake is to be preserved. I I 1.0 INTRODUCTION I Lake Boon is located in Hudson and Stow, Massachusetts (Figure 1-1), tributary to the Assabet River. The watershed includes land in the both towns, and is dominated by forest with dense residential I development surrounding the lake. I Historically, Lake Boon has been an important recreational resource for the residents of Stow and Hudson—swimming, boating, and fishing I are all popular activities. At one time, the cottages surrounding the lake were popular for summer vacations of Boston area residents, however, most I have been converted to year-round homes. In more recent years, the condition of the lake deteriorated because I of increased algae and aquatic plant growth, interfering with established recreational pursuits. Initial attempts to control weed I growth began in the 1960fs with chemical and mechanical controls. These were only marginally successful, and continued problems led to a 1978 study by the Metropolitan Area Planning Commission (MAPC). "A I Management Program for Lake Boon: Interim Report" was issued by MAPC in January 1979, and addressed land use and zoning issues in the I watershed. In 1979-1980, the Massachusetts Division of Water Pollution Control I (DWPC) conducted a year-long study of the lake. This effort included water quality monitoring, hydrologic and nutrient budgets, and an I analysis of potential management/restoration strategies. However, restoration measures for the lake were not fully evaluated. The I present study is designed to update the findings of the DWPC study, and to provide a more detailed analysis of feasible restoration techniques- The study began in the summer of 1985, and was partially I funded through the Massachusetts Clean Lakes Program (Chapter 628).