Table 1. Water quality on July 26, 2014 at the deepest point in Lake Garfield.

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1 Water Resource Services Inc. 144 Crane Hill Road Wilbraham, MA Dr. Michael Germain Friends of Lake Garfield c/o August 26, 2014 Dear Dr. Germain: I am writing to follow up on the July 26, 2014 survey of Lake Garfield and our subsequent discussions. We examined water quality with field equipment, but did not send any samples to the lab. I looked at phytoplankton and zooplankton, indicative of water quality and fish community structure, but most effort was focused on the plant community. There are two main issues of concern relating to plants in Lake Garfield: invasive Myriophyllum spicatum (Eurasian watermilfoil) and seed producing species of Potamogeton (pondweed), particularly P. amplifolius (bigleaf pondweed) and P. richardsonii (Richardson s or clasping leaf pondweed). Water Quality The lake thermally stratifies in summer, with a boundary near the 6 m (20 ft) depth (Table 1). Below that depth, the water is colder and has much less oxygen. Most fish cannot survive below a water depth of 7 m (23 ft). The ph is slightly alkaline in the upper water layer and slightly acidic in the lower water layer, but within normal bounds in both. Turbidity increases with depth, becoming elevated at 5 m (16.5 ft) of water depth. Visibility, as determined with a Secchi disk, is 4.9 m (16.2 ft), which is high for Massachusetts lakes at this point in summer. While the loss of oxygen in deep water is undesirable, it is a natural state for most lakes. Otherwise, assessed water quality will support all desired uses of the lake. Table 1. Water quality on July 26, 2014 at the deepest point in Lake Garfield. Date Time Depth Temp DO DO Sp. Cond ph ORP Turbidity Secchi MM.DD.YY HH:MM:SS meters C mg/ l % Sat µs/ cm Units mv NTU meters :22: :23: :24: :25: :26: :44: :45: Plankton Page 1

2 Water Resource Services Inc. 144 Crane Hill Road Wilbraham, MA Phytoplankton, or algae floating in the surface waters of the lake, included mainly diatoms and cyanobacteria at low densities. The quantity is not a concern at this point, and corresponds to the high water clarity. However, the quality is a concern, with cyanobacteria including forms that sometimes bloom and could cause taste, odor or even toxicity issues. Included are the genera Page 2

3 Aphanizomenon and Anabaena (potential problem genera) along with Limnoraphis and Gomphosphaeria (less problematic genera). Current abundance does not signify a problem, but an increase would suggest overfertilization and a low ratio of nitrogen to phosphorus. This could be a function of watershed inputs, but is more likely to be an issue of internal recycling. Further testing later in summer would be a good idea, and the Friends of Lake Garfield should consider adopting at least a rudimentary monitoring program. Zooplankton are small animals, mostly crustaceans, that swim in the lake. They graze on algae or eat each other, and are food for small fish. They are an important link in the food chain. Lake Garfield has a moderate density of zooplankton with a range of types, including the rotifers Conochilus and Kellicottia, the copepods Mesocyclops and Diaptomus, and the large cladoceran Daphnia galeata. The size distribution is also moderate, a very good indication of balance between fish and zooplankton and appreciable grazing pressure on algae. The cyanobacteria are not especially edible by the zooplankton, but the diatoms are. Plants 2013 was a banner year for pondweed species; growths were dense and nuisance conditions were observed in at least the small basin was a lower growth year for these species, possibly a function of the severe winter. Conditions with seed producing plants will vary substantially from year to year, while perennial plants like the milfoil tend to be more stable. Drawdown impacts plants out to about 6 ft of water depth, perhaps to 8-9 ft in a deep drawdown (6 ft) year. The impact will be mainly felt by perennial species, those that overwinter in a vegetative state, such as milfoil. Seed producers such as pondweed are favored by drawdown, both because of the control exerted over perennial species and because seed germination is often stimulated by exposure to air and cold. The survey on July 26 th indicated a diverse plant community with fairly few areas of high density. There are nearshore areas where pondweeds and related species were dense, but most areas were less impacted than in Milfoil was present in shallow water, within the drawdown zone, but never at high density. The distribution of milfoil is indicated in Figure 1, as supported by Table 2, and includes mostly scattered individual plants around the periphery of the southern (big) basin. There is one large patch of dense milfoil growth covering perhaps 1.5 acres slightly south of the connector between the two main basins, in 6-8 ft of water. One large patch of Stuckenia pectinata (sago pondweed) was also observed, in the smaller basin. The sago pondweed patch may or may not persist next year, but the milfoil patch is likely to remain and expand; this patch will be a source for colonization of other areas too, being just beyond the influence of drawdown. It appears that drawdown minimizes milfoil growths in water <6 ft; many shallow areas would be expected to have dense growths if not for the drawdown. The drawdown may be all that is Page 3

4 needed to manage milfoil in shallow water; scattered growths could be handpulled to limit expansion, but the observed level of growth in both 2013 and 2014 was not a major threat to plant community dynamics, aquatic ecology, or human uses of the lake. Management of denser growths in deeper water would be advisable to limit impacts. Certainly the one patch observed in Page 4

5 Figure 1. GPS point locations from July 26, 2014 survey. Table 2. Descriptions of conditions at GPS points shown in Figure 1. GPS point # Observations 185 Dense sago pondweed patch (approx 1 ac) 186 Milfoil scattered along shore from pt Start of large milfoil patch (north end) - in about 6-8 ft of water 188 End of large milfoil patch (south end) - approx 1.5 ac 189 Scattered milfoil growths in shallow water 190 Scattered milfoil growths in shallow water near inlet 191 Scattered milfoil growths in shallow water 192 Deep hole, water quality and plankton station Phragmites patch. Note that second patch not recorded on GPS, in bigger basin 193 on western shore Page 5

6 2014 was dense enough to disrupt plant ecology, fish habitat, and human uses in the affected area. We did not spend a large amount of time viewing growths in water >10 ft deep, and with the high water clarity, milfoil could be a problem out to about 14 ft of water depth. No problems were observed in 2014, but a more detailed survey might be worthwhile in Management Needs and Options The observations and suggestions from 2013 remain valid, and the 2013 memo should be reviewed when developing a plan. Considering what was observed in 2013 and 2014, I would suggest the following: Management needs in water <6 ft deep are mainly focused on native seed producing plants that can grow densely in the drawdown zone. There will be substantial interannual variability that will not be particularly predictable. If growths interfere with lake uses, mainly swimming and boating, mechanical harvesting is likely to be the simplest approach to reducing those growths. A mechanical harvester could be purchased, but the cost (about $200,000) and operational needs (training, insurance, maintenance, and limits on how much area can be addressed in a short period of time) suggest that contract harvesting may be more advantageous. About a week of harvesting time from a company devoted to that type of work should be sufficient to get most growths under control. The cost would be on the order of $10,000. Harvesting should occur before seeds can be produced and released, minimizing future growths, although seeds do not all germinate the following year. Harvesting over multiple years may be necessary where dense growths are found each year, to exhaust the existing seed reserves in the sediment. Appropriate harvesting for the problem seed producers in Lake Garfield should occur in June and possibly early July. Handpulling of milfoil in shallow areas could be conducted by volunteers or paid staff. This could be done with a pontoon boat from which shallow growths could be detected and snorkelers or divers could be dispatched to pull up milfoil by the roots. Someone should be prepared to pick up floating fragments with a pool skimmer or similar device; fragment production is to be expected during handpulling operations. On a paid basis, a crew could operate for perhaps $3000 per day and might need a week to cover the affected shallow areas of Lake Garfield. Where milfoil patches occur, with high density over an area more than a quarter acre, handpulling is still possible, but tends to be slower and messier, with much fragment production. Coverage with bottom barriers such as Aquascreen or similar materials can be effective, and bottom mats can be re-used in other areas for many years, but the initial cost is high, on the order of $40,000 to $50,000 per acre. Alternatively, suction harvesting can be applied. Diver assisted Page 6

7 suction harvesting (DASH) is basically handpulling aided by a suction tube into which plants can be fed. Plants, water and any associated sediment are pulled through the tube to a bagging and filtering station at the surface, on a float or pontoon boat. Plants are caught in the bag and water and fine sediment are returned to the lake. Turbidity generation is local and temporary. A cost of about $10,000 to $12,000 per acre should be anticipated, with two harvesting periods per targeted patch. The second period is usually a month or more after the first period, allowing removal of any recovering plants, and is sometimes conducted the following year. The surveys conducted in 2013 and 2014 offer a useful but limited snapshot of conditions in Lake Garfield. A slightly more robust monitoring program is recommended to support management efforts. Water quality as performed here, plus samples at the surface and bottom for nutrient levels (analyzed by a certified lab) should be collected twice per year, in May or June before stratification and in August or September during late stages of stratification. The cost for lab testing would only be about $500 to $750 per year. Plant monitoring might be conducted as part of a handpulling effort if involved parties are properly trained, or can be conducted under contract by a qualified outside party at a cost of about $3000 per year. Permitting for plant management will involve filing a Notice of Intent under the Wetlands Protection Act, from which an Order of Conditions should be received, the actual permit to perform the work. The local Conservation Commission issues this permit, in consultation with the Department of Environmental Protection. Nothing suggested here should represent a conflict with the interests of the WPA, but it will be necessary to consult with the Natural Heritage and Endangered Species Program (NHESP), as Lake Garfield is apparently home to one or more listed species. No other permit is needed for any recommended action, and unaided handpulling and bottom barrier deployment can be covered under a Determination of Applicability, in which the Conservation Commission can declare that the impacts of those actions are inconsequential and do not require further permitting. However, in light of the presence of at least one state listed protected species and the desire to possibly conduct mechanical harvesting or DASH, it is advised that all possible actions be included in one Notice of Intent. The resulting permit can be renewed by simple Conservation Commission action after three years. Contact me with any questions. An invoice for services to date in 2014 accompanies this letter report. Sincerely yours, Kenneth J. Wagner, Ph.D., CLM Water Resources Manager, WRS INC. Page 7