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HomeMy WebLinkAbout1967-09-25-REC-rpt "Cortell Report".pdf CABLE: BIOCORT BOSTON JASON M CORTELL iorMatnagithera 192 WORCESTER STREET ROUTE 9 WELLESLEY HILLS, MASSACHUSETTS 02181 AREA CODE 617 235-0777 JA REPORT OF A BIO-ENGINEERING STUDY OF THE OLD LEXINGTON RESERVOIR FOR THE RECREATION COMMISSION TOWN OF LEXINGTON, MASSACHUSETTS I BACKGROUND Following its early use as a water supply storage area for the Town of Lexington, residents have viewed the "Old Res" on Marrett Road as a possible site for a i Town recreation area Thoughts along these lines apparently have been discussed by Lexington residents informally Until this Study, the most recent attempt to determine the feasibility of developing a recrea- tion facility at the Old Lexington Reservoir was made by the Town Planning Board back in 1955 At that time, it was determined that the Reservoir was unsuitable for swimming purposes , primarily because the water supply was considered to be "badly polluted " In mid-July 1964, this office was contacted by the newly-formed Lexington Conservation Commission At that time, interest was expressed in the possibility -2- of once again reviewing the environmental factors affecting water quality at the Reservoir with the possible aim of developing the Marrett Road site as a natural history area, as well as a "swimming hole" for the Town' s increasing population An initial inspection was made of the Reservoir in early August, 1964, and later that month a pre- liminary report was given to a Board Meeting of the Conservation and Recreation Commissions That report indicated that there was, indeed, a possi- bility of developing the Old Lexington Reservoir as a swimming area, and that a bio-engineering study be commenced to gather data as to the present status of the water quality After two unsuccessful attempts to have the Study placed on the Town Warrant, the joint efforts of the Recreation and Conservation Commissions success- fully obtained unanimous Town Meeting approval for the Study After several months delay, in July, 1966, the Board of Selectmen advised the Recreation Commission to assume responsibility for the Study and immediately thereafter, this office was advised to commence the field study 1 -3- Because of the unusual drought conditions which existed through the fall of 1966, this office did not feel it advisable to submit a report in time for action by the 1967 Annual Town Meeting Instead, it was determined that additional field study would be advisable, particularly because of the dramatic change in the water supply conditions This afforded us an additional opportunity, during the spring and summer of 1967, to further evaluate the problem under maximum ground water conditions II A BIO-ENGINEERING STUDY PROGRAM A scientific study of the Lexington Reservoir and its watershed system, including the physical, chemical, and biological conditions present therein A. This study program included a complete series of field and laboratory tests to determine 1 The presence and possible sources of bacterial pollution entering the Reservoir 2 The nature and extent of contami- nation by detergents and other chemical pollutants. 3 The presence, strength, and directions of water flow and currents within the Reservoir 4 The presence and extent of aquatic weed growth 5 The physical nature of the Reservoir bottom and its relationship to aquatic weed growth -4- B Feasibility study of the various modes of action available and/or required to create a recreation area and natural history park at the Old Lexington Reservoir III RESULTS A The Site 1 The body of water, known as the Lexington Reservoir, covers an area of approximately 5 4 acres The average depth is 5 feet 2 The Reservoir has two major sources of water Its major source of water is the water table from which spring water percolates throughout the year. Its secondary source of water is derived from two streams which flow north, combine above Marrett Road, and flow into the shallow east end of the Reservoir. 3 The area surrounding the body of water is heavily wooded The Reser- voir area (land and water) covers a total of 18 acres , and is bounded on the north by the Bridge School B Water Quality 1 Chemical tests taken at the Lexington Reservoir over the past two years indicated that the level of water quality was close to, if not some- what above, the mean water quality levels found in Massachusetts pot- able water reservoirs. 2. Water analysis of the two streams flowing into the Reservoir exhibited no unusual chemical characteristics, other than those which are normally found in surface water drainage areas TABLE I CHEMICAL ANALYSIS OF LEXINGTON RESERVOIR PARTS PER MILLION ( p.p m. ) TEST JULY 20 , 1966 DEC 13, 1966 JUNE 23, 1967 Dissolved Oxygen 9 .0 8 1 12 . 0 B 0 D 0 4 0 . 1 0 2 Iron 0 71 0 35 0 35 Turbidity 20 0 -5 0 -5.0 Color 40 0 15 0 20 0 pH 6 8 6 0 6 3 Silica 3. 1 4 . 4 3 7 Iron Oxide 0 28 1 0 0 3 Magnesium 1 9 1 2 1 8 Sodium & Potassium 4 0 4 1 4 0 Sulfates 16 8 12 0 13 8 Chlorides 6 5 4. 5 5. 5 Alkalinity 38 47 40 Hardness (as calcium) 60 48 55 Detergents as ABS Neg Neg Neg i -5- 3. Bacteriological examination of the water within the Lexington Reser- voir indicates that the levels of bacteria are well within the safe limits of water use and exhibit indications of no external pollu- tion 4 With the exception of the natural build-up of bacteria from non-fecal surface drainage, the streams which flow into the Lexington Reservoir exhibit no evidence of pollution 5 The only water quality problem noted was in the Tufts Road area where ground water seepage of a high iron content in the form of ferrous oxide was observed 6 On two occasions , surface drainage flowing into the Lexington Reservoir exhibited discoloration and odors Further investigation of these two problems revealed that some form of contaminant had been introduced into the catch basins above the Reservoir, probably on Marrett Road The presence of pesticides in the surface water drainage was not detected However, it must be assumed that some pesticide material may find its way into the Reservoir as a result of either the East Middlesex Mosquito Control work or from private sources 7 It is most izjtpprtant to point out that no fish kills or unusually high algal blooms occurred during the two-year study C Limnology 1 A study of the physical nature of of the Reservoir indicated that the maximum depth was between 7-8 feet, while the average depth was set at 5 feet TABLE II BACTERIOLOGICAL EXAMINATION OF LEXINGTON RESERVOIR AND STREAMS July 20, 1966 Res Stream Stream A Standard Plate Count per M.L @ 35°C 160 290 400 Coliform Bacteria per 100 ml (M F ) 95 120 110 December 13, 1966 Standard Plate Count per M.L @ 35°C 75 130 110 Coliform Bacteria per 100 ml (M F ) 3 15 10 June 23, 1967 Standard Plate Count per M.L @ 35°C 120 190 360 Coliform Bacteria per 100 ml (M.F ) 21 44 37 1 August 17, 1967 Standard Plate Count per M.L @ 35°C 390 420 400 Coliform Bacteria per 100 ml (M.F ) 25 38 40 1 DIAGRAM - A Stream, 3 3 6 Q 5 Depth 6 g 7 5 RQOd `d ti � n G • -6- 1 2 Oxygen was found at all levels indicating limited thermal stratification 3 The bottom of the Reservoir is composed of a clay-sand composi- tion and appears to be suitable for the development of recrea- tion facilities 4 As a result of water control manage- ment, and the unusually heavy rain- fall this past year, the level of the Reservoir did not drop signi- ficantly, indicating that during periods of normal rainfall, sufficient water is available in the watershed and the aquifer to maintain sufficient water depth for recreational use 5 With the absence of natural water currents of any significance, the utilization of artificial circu- lating equipment, supplemented by artificial aeration, appears to be a logical step toward elimination 1 of the problems associated with stagnation at public bathing facilities Water flow tests indicate that ideal conditions can be created at a minimum cost D Development 1 After a study of the water levels , the bottom contour, and the shore- line, the development of a recrea- tion facility on the northeastern shoreline between the dike and the dam appears feasible 2 Adjustment in the contour of the shoreline is possible without major construction and development of a suitable beach area can be accom- plished with a minimum of adjust- ment in present grades and eleva- tions 1 -7- 3 The clearance of brush appears to be the major work project and can be effectively carried out by the Town itself 4 Vehicle parking can be accommo- dated at the rear of the Bridge School on Middleby Road This area, already blacktopped, can accommodate about 200 cars 5 By the construction of a small footpath through the natural wooded area, which separates the Reservoir from the school, access to the recreation area can be accomplished The location of the parking facility and the proximity to the bathing beach eliminates the necessity for parking vehicles along Marrett Road. 6 The isolation of the recreation area (as well as the parking facility) from the surrounding residential dwellings should alleviate some of the anticipated noise level which is typical of a town recreation facility. 7 Development of the natural area around the Reservoir for fishing, nature study and possibly picnicking have been reviewed and at this time appear to be feasible IV SUMMARY Based on the results submitted herein, it appears that the development of the Lexington Reservoir as a Town recreation facility is biologically feasible The facility can be developed at a reasonable cost to the Town, accommodating upwards to 300 swimmers at any one time -8- The advantages of a natural swimming area, as opposed to a pool, are self-evident A schedule of the estimated cost of development is attached t7� S 6-‘ -trjer / J SON M. CORTEL onsultant Biologist p Submitted. 9/25/67 TABLE III LEXINGTON RESERVOIR ESTIMATE OF DEVELOPMENT COSTS BEACH PROPER Removal of all undesirable herbaceous and woody plant material under 3" D B H Area approximately 15 ,000 sq ft. Note Can be done by Lexington Tree Department $ 300 00 Sterilization of submerged and above-ground beach areas lying directly under those areas to which sand is to be applied Area approxi- mately 5,000 sq ft 150 00 Beach sand, 150 yards 600. 00 WATER QUALITY IMPROVEMENTS Flow Developer 3,200 00 Aeration System 1,800. 00 Electrical work 1,500 00 Bacteria checks , per season 60 .00 Algae control, per season 150 . 00 OTHER Comfort Station 2 ,500 00 Pavement (asphalt) 10 ' walkway to Bridge School, 2 ,700 sq ft 950 .00 Picnic tables 250. 00 Buoys and lines , life preservers, rope 100 . 00 Lifeguard stands 100 00 Sub-total $11, 660. 00 Contingencies 1,200 .00 Total $12 ,860 00 1