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Little Island Lake Water Quality Survey and Protection/Improvement Alternatives 2001 by Wade/Trim 3933 Monitor Road Bay City, MI 48706 Tel: 989-686-3100 and Aquatic Consulting Services 4515 Verity Road Sanford, MI 48657 989-687-2737 Table of Contents Chapter Page Introduction 1 Water Inputs and Outflows 2 Water Quality 5 Biology 9 Discussion and Recommendations 13 Summary of Recommendations 18 Figures Page Figure 1. Lake Huron Hydrograph, Army Corps of Engineers 2 Exhibits Exhibit 1. Little Island Lake Watershed Area Exhibit 2. Little Island Lake Area Exhibit 3. Little Island Lake Groundwater Slope Exhibit 4. Little Island Lake Water and Phosphorus Budget Appendices 1. Little Island Lake, Water Quality Measurements 2. NTH Consultants, Ltd. Proposal, Scope of Work, and Estimated Fees 3. Little Island Lake, References INTRODUCTION The residents of Little Island Lake have expressed concern over several quality aspects of the Lake. Water depth has diminished over the last few years, muck seems to have built up, and the fish production is reported to be low. In an effort to address these issues, and other quality aspects of the Lake, the Little Island Lake Improvement Board initiated the present study in January of 2001. There are dozens of lake improvement protection and enhancement methods available, but knowing which are appropriate is the key. This study was undertaken to first understand the major environmental factors affecting Little Island Lake, and to provide recommendations for the most appropriate measures to help preserve and protect the Lake. As the study progressed, it was discovered that Little Island Lake is quite unique. It has greatly fluctuating water levels, little volume, a very long nutrient retention time, low fish production potential, and yet has very clear and mostly weed free water. The overall lake quality is quite good, but this position is precarious. It is for these reasons that many conventional lake improvement measures will not work and, in fact, could be detrimental to the Lake. We encourage the Lake Improvement Board, now and in the future, to be very cautious about implementing any measures that are not contained in this study without a thorough review and very good evidence that the measure will work on this particular Lake. The following pages are written for a quick comprehension of the major important points of the study. To that end, much of the detailed work and analysis is left to the appendices rather than in the body of the report. The reader should refer to the appendices and the literature sources if additional detail is desired. WATER INPUTS AND OUTFLOWS The amount of water in the Lake is of great concern. During the time of this study, the water level was approximately four vertical feet below normal. This low level has a dramatic impact on a lake that is shallow to begin with. Although historical data is sketchy and most information is from human memory, it is apparent that Little Island Lake has gone through previous times of low water level. In May of 1999, the level was low enough to prompt one resident (McGurrin 2001) to begin measuring the level from a fixed shore point. The low level worsened by that September and there has been no overall water recovery through November of 2001. Equally low levels have been reported in the late 70's and earlier in about the 1950's. There may have been others. The low lake levels correspond quite directly with years of low lake levels in Lake Huron, which corresponds directly with lack of precipitation throughout the Great Lakes watershed (Figure 1). These periods of low rainfall seem to occur in cycles of about ten to fifteen years and have a dramatic effect on lake levels. Low rainfall amounts over the last three years in the mid-Michigan area have caused some ponds to dry up completely. Records from the Houghton Lake weather station (2) show that 1997 was the last good precipitation season, with the years 1998 through 2000 being below normal. Figure 1. Lake Huron hydrograph, Army Corps of Engineers Precipitation directly on the Lake helps replenish the Lake water. Equally important is the water that falls in the watershed and seeps slowly into the Lake through the ground. The watershed for Little Island Lake lies to the north and northeast and encompasses only about 570 acres (Exhibit 1). The precipitation that lands on this area seeps into the soil and works its way to the south entering Little Island Lake in the northeast corner. Three lines of evidence show that the northeast corner is the groundwater input area: topography, groundwater slope toward the Lake, and generally colder water in this area indicating groundwater seepage. Part of the difficulty with water volume in the Lake is that the groundwater recharging watershed is not very large, only ten times the size of the Lake. As this groundwater is depleted in a series of years of low rainfall, the source of water to the Lake is diminished and the water level drop in the Lake cannot be made up by occasional rainfall. It takes a lot of precipitation over a long period to make up the groundwater and, hence, the Lake level. Water leaves the Lake through evaporation from the surface and through the ground on the west and south sides of the Lake. Evaporation can be significant during hot summer months, but rainfall usually makes up much of this immediate loss. In normal years, a drop of a foot to a foot-and-a-half of water level can be expected over the summer and the water level should be recovered with autumn rains. The persistent four feet of loss in recent years is truly excessive. Little Island Lake sits in a basin of sand, and just as groundwater enters the Lake through the sand, it also leaves the Lake through the sand. The overall elevation changes are from a high area in the watershed area (see Exhibit 1) to a lower area west and south of the Lake on the Au Gres River bed. The groundwater follows this northeast-to-southwest path through the Lake with the Lake as a temporary exposure of the groundwater. Six temporary groundwater wells were used to assess the direction and slope of the groundwater near the Lake. Exhibit 3 shows the summer groundwater conditions at the various locations. In general, the groundwater elevation near shore is above the Lake surface in the northeast corner of the Lake, level with the Lake surface on the north and east shores, and below the Lake surface at the west end and south corner. There is a considerable vertical drop between Little Island and Floyd Lakes, seven vertical feet over a 400-foot horizontal distance. However, it does not appear that a large quantity of water leaves Little Island Lake through this corridor. The soils appear to be less pervious because of the road construction. Floyd Lake was also very low during the summer of 2001. If there were great water loss from Little Island to Floyd, it is likely that Floyd would maintain a more normal lake level. The west end of Little Island Lake appears to be the major outlet for groundwater from the Lake. The groundwater slope away from the Lake was most severe in this area (Exhibit 2). The groundwater velocity was also measured between two wells using a dissolved ionic substance. It was found that the groundwater movement was approximately four inches per hour away from the Lake at the western most location in September of 2001. Unless there are unusual soil or rock layers, most of the groundwater enters and exits a lake in the top few feet of shoreline. This appears to be the case for Little Island Lake. There were no signs of active springs within the Lake during 2001 and it is likely that the groundwater simply seeps in around the margin just under the water surface where the sand is exposed. In years of good precipitation when the groundwater is piled higher and moving faster in the watershed, it may be that the seepage is visible in spring-like seeps. But in 2001, this was not the case. In addition to precipitation directly on the Lake and groundwater input, water also enters as overflow from Round Lake. In 2001, the overflow discharged water for only a few weeks in the spring. In more normal precipitation years, the overflow is more substantial yet short in duration. A water input budget was developed using the measured values for the various water sources. The data was then adjusted to a more normal year's precipitation so that the inputs reflect a long-term situation and not just a low water condition. Exhibit 4 shows the results. Since Little Island Lake has no surface outflow, evaporation and groundwater discharge account for all the water loss. Evaporation accounts for about one third of the loss in normal years and groundwater loss is about two thirds. In words, the hydrological picture for Little Island Lake that emerges is as follows: There is a groundwater flow that starts to the north of the Lake and the water seeps slowly from the north to the southwest. Along this path a depression occurs which is Little Island Lake. The water flows through the Lake and out the west side with evaporation taking place but most of which is returned by rainfall directly on the water surface (although sometimes not at the appropriate time of year when the Lake needs it). In years of good precipitation amounts, the groundwater in the watershed mounds up and moves into and through the Lake rather fast, filling and leaving the Lake in about one year's time. In years of low precipitation, the groundwater continues to leave the Lake at about the same rate but the input water at the other end is greatly reduced. Aggravating this situation is increased evaporation without adequate summer storms to make up this loss. The Lake level continues to drop with the water leaving through the sand that is in the upper few feet on the west side. Little water leaves through the muck at the bottom and sides of the Lake. So as the level gets lower and lower, the rate of loss slows down. It may take several years of normal or above average precipitation to recover the normal water levels. WATER QUALITY There is no single measurement of water quality for lakes. Measurements of several chemical and biological parameters are taken to give an overall picture of the lake's quality. Alkalinity is a measure of a lake's dissolved carbon hardness and its ability to withstand pollution inputs such as acid rain. Alkalinity in natural lakes ranges from lows of about 50 milligrams per liter (mg/l) to over 200 mg/l with values over 100 being considered hardwater lakes and values below 100 considered "soft water lakes". The alkalinity readings in Little Island Lake varied throughout the season from a low of 75 mg/l and a high of 100 mg/l. Little Island should be considered a soft water lake. The low alkalinity does not hurt the Lake directly but does increase its susceptibility to change. Low alkalinity lakes do not utilize their nutrients well and productivity is limited. Low alkalinity lakes are more susceptible to noxious algae blooms and are more impacted by acid rain. Although no overtly detrimental effects were noted as yet, the low alkalinity adds to the Lake's precarious position. Water pH is a measure of its acidity. Values less than 7 are acidic and values greater than 7 are basic. Lakes usually vary between pH of about 6.5 to 8.5. Little Island average pH was 8.3 during the time of this study. This is a good measurement and no adverse affects from low pH are expected. Dissolved Oxygen is necessary in water to support fish, plants, and most insects. Dissolved oxygen levels vary between 0 and about 11 parts per million (ppm) in most open waters. Levels of about 3 ppm are necessary to support warm water fishes such as bluegill and bass. During the summer testing, dissolved oxygen levels were entirely sufficient to support normal plants and animals in the Lake. Measurements were above 10 ppm throughout the Lake. There is not enough depth to produce the common layering of warm and cool water in Little Island Lake. That takes place usually below twelve feet of depth. The deepest spot in Little Island was eight feet (although at normal water levels it would be closer to twelve). During periods of extended ice cover, the dissolved oxygen may be reduced to a dangerous level and cause fish kills. There is no direct evidence that this has happened in recent years but there is a lack of large fish in the Lake and the larger fish are the most susceptible to low dissolved oxygen levels. Also, the low water volume and the heavy muck buildup favor low winter oxygen levels. This is a dangerous set of conditions for fish life and measures to increase the winter water volume of the Lake would be very beneficial. Good Transparency of the water is important for general recreation. Some waters are so turbid from suspended algae and silt particles that they are not attractive for recreation. Transparency is measured by a Secchi Disk, which is lowered into the water until it disappears from sight. Lakes are considered to have adequate transparency if the disk reading is six feet or more. The disk could be seen at all test dates to the bottom of the Little Island Lake (eight feet) although there was noticeably less transparency during the August testing. Conductivity is a measurement of the dissolved salts in the water that enable the water to conduct electricity. Values in lakes generally range between 100 and 400 with the soft water lakes being on the low end of the range. Little Island Lake measurements of conductivity were between 130 and 210 depending on location and season. Nutrients are necessary for plant growth, but excess in lakes can be dangerous. Lakes function very well with nitrogen levels below 0.3 mg/l but above that level excessive algae and rooted plants often occur. The summer level of nitrogen in the Little Island Lake was 0.53 mg/l. This nitrogen level is somewhat excessive and indicates that adequate nitrogen exists for massive growth of weeds and algae. However, there is very little plant growth persisting in the Lake. Phosphorus is the nutrient of even greater importance than nitrogen. Phosphorus in very small amounts stimulates massive weed growth and algae blooms, particularly when adequate supplies of nitrogen are available. Levels of about 0.03 mg/l phosphorus is considered the threshold for this nutrient. Above this level, the lake is in danger of excessive plant growth. The open waters of Little Island Lake measured very low in phosphorus, 0.01 mg/l or below. This is desirable for lake quality and indicates that phosphorus is limiting the algae growth in the open water of the Lake. The news is not all good, however. Massive amounts of phosphorus are very near in the sediments. Testing of the upper layer of sediment showed 640 mg/Kg of phosphorus. Phosphorus free water allowed to stand over this sediment for just 24 hours in laboratory conditions accumulated the phosphorus very readily from the sediments and had an end value of 0.050 mg/l of phosphorus, more than enough to grow excessive weeds and algae. Phosphorus enters the Lake from a variety of sources. Any dust, dirt, or organic matter contains phosphorus. Therefore, tree leaves, grass clippings, bird droppings, eroded topsoil, etc. should be kept out of the Lake. Rain contains phosphorus principally from the dust that forms the nucleus of the raindrops. The native soil around the Lake is moderately high in phosphorus, although the phosphorus tends to remain stationary unless the soil is disturbed or washed into the Lake. Groundwater moving through the soil contributes a little phosphorus, but only in very minor amounts. Septic fields are a potential source of phosphorus. Humans contribute about 2.2 pounds of phosphorus to a septic field each year of continuous habitation. How much reaches the Lake depends on the filtering capacity of the soil and whether or not the soil downstream of the field has been saturated with phosphorus. Some phosphorus also enters from Round Lake, but the concentration was low in the overflow (less than 0.01 mg/l) and therefore contributes only a small amount of phosphorus. All of these phosphorus sources were measured and/or calculated from literature values and placed in what is called a "Nutrient Budget" so the relative amount of the inputs are apparent. Exhibit 4 combines the previously noted water budget with the nutrient budget. The "phosphorus limit" bar at the bottom of the graph relates directly to the phosphorus input blocks above it. All of the phosphorus amounts to the right of the "Dangerous Loading" line are excessive and are stressing the Lake. It is obvious that Little Island Lake is receiving excessive amounts of phosphorus, yet it is also obvious that removing enough of the inputs to get the phosphorus level down to the "permissible limit" would be impossible. The conclusion here is that nutrient control alone will not be enough to protect and restore the Lake; although as much reduction of input as possible is wise to limit the averse effects. The excessive amount of phosphorus entering the Lake and the Lake's low concentration of phosphorus in the water seems like a contradiction until we consider the sediments. All the evidence indicates that the phosphorus resides primarily in the sediments, and the sediments are very thick. We used a 30?foot coring tube to probe the sediments and in the west bay we never reached the native sand bottom. In fact, the coring tube sank by its own weight to the full 30 feet, and we were only in a little over 5 feet of water. Elsewhere in the Lake, it had to be pushed the last several feet, as the sediment becomes more compact near the bottom. Therefore, at least in the west bay, there is likely about 35 feet of sediment, or more, on the Lake bottom. Putting all this information together, the path of phosphorus through Little Island Lake is as follows: Phosphorus enters the Lake from dry fall (primarily leaves, some dust and bird droppings), direct rainfall, and septic field groundwater from the homes on the east and northeast sides of the Lake. This phosphorus is taken up by microscopic algae cells, but these algae cells do not live very long. Algae is eaten by small crustaceans called zooplankton. The zooplankton excrete pellets that fall to the bottom producing sediment (muck) that contains most of the phosphorus (a pound of phosphorus for every three tons of sediment). The phosphorus stays in the sediment as long as the water above is well oxygenated and rooted weeds do not become plentiful. The desirable part of this scenario is that the water stays clear and useful. The bad part is that the muck continues to build and the clear water situation is highly dependent on a good zooplankton population. This good situation is also dependant on the very flocculent nature of the sediments that do not furnish a good foothold for rooted plants and does provide shelter for the zooplankton. This is a rather precarious situation. Any disruption in the zooplankton or the sediment characteristics or the rooted weed growth will throw off this delicate balance. BIOLOGY Algae are the beginning of the food chain in lakes. It is odd to us humans that a plant we can not see without a microscope is the most important plant in the lake to the other animals that live there. Algae are the plants that first absorb the nutrients phosphorus and nitrogen and make it into plant material. Small crustaceans called zooplankton eat the algae; and minnows and small fish eat the zooplankton. This is the primary path of food in lakes. The free-floating algae in Little Island Lake was dominated by desirable types most of the summer except for the month of August. Blue-green algae types are the most likely to cause problems as they tend to float on the very top of the water and cause scums to form. Also, blue-greens are not as readily eaten by the zooplankton and therefore are harder to control. In August, a blue-green species gained the upper hand and became the dominate algae in the Lake. The cooler temperatures of September allowed more desirable species to again dominate, but the summer shift in species shows again how susceptible the Lake is to unwanted changes. The number of algae cells per milliliter of water is also important. If the numbers stay low (less than about 2,000 per ml) then the water stays clear and usable. For most the year, the numbers were low in Little Island Lake (71 to 1200 per ml). But in August, the algae cell concentration jumped to 7,400 per ml. and corresponded to the time of lower Secchi Disk transparency. This algae increase may be harbinger of things to come. Zooplankton are the tiny insects that also move freely throughout the open water of the Lake and are the primary consumers of the algae. Large numbers of zooplankton graze on the algae keeping it within desirable limits. As long as a lake contains good numbers of zooplankton, and the zooplankton are large enough in size, the lake seldom has problems with excessive algae. Little Island Lake had very high concentrations of zooplankton during 2001. In most lakes, 30 or more zooplankton per liter is enough to keep the algae under control. Little Island had concentrations between 82 and 1455 per liter. These are very high numbers and it is this abundance of zooplankton that is primarily responsible for the clear water of the Lake Size is also important in the zooplankton population and the Lake started the summer with good sized zooplankton with an average length of 0.61 mm. Average length above 0.50 is desirable. By July, however, the average zooplankton length was 0.32 mm and by August is was 0.28 mm. In September, the zooplankton length recovered somewhat to 0.30 mm. Zooplankton size is directly related to how many small fish are preying on them. The more small fish, the smaller the zooplankton size because the fish can see the larger zooplankton and feed on them more directly. Small Fish are the next step in the Lake’s food chain. Minnows rely on zooplankton for food their entire lives and the fry of game fish rely on zooplankton until they reach several inches long. In a high quality lake, there is a small number of small fish. When game fish are young, they grow quickly on zooplankton, but as they reach a few inches long, they switch to a diet of other insects, minnows, and smaller fish. This produces a lake with a dominance of large fish: bluegills eight inches and larger, bass 16 inches and up, etc. But man often interferes with this end product by removing the larger fish and making an artificial situation where the lake is dominated by smaller stunted fish. This situation is not good for lake quality, as it diminishes the zooplankton and allows the algae to grow to excess. The above photo shows a sample of fish from Little Island Lake taken in early September. The first thing to note is that only two of the group are sizeable enough to be considered catchable and eatable. The other 31 fish are small, "not worth bothering with". They are stunted. Growth analysis shows that the one, two, and three year old bluegill and all the perch are all growing below the state average. There are too many panfish for the available food source. They are all competing for little food with none of them getting enough for proper growth. All the small fish examined had nothing in their stomachs. Again there seems to be a contradiction. There is plenty of zooplankton, why are the small fish not feeding on them? The answer is again, the sediments. Zooplankton are primarily nocturnal in a lake as shallow as Little Island. They move up near the surface to do most of their feeding at night when the fish cannot see them. During the day, the zooplankton go as deep as they can and in Little Island that means they are down and among the sediments. The sediments in this Lake are very, very flocculent, meaning that it is a very loose material more like a cloud of particles for the first few feet. When we drop our instruments into the sediment to collect samples, the instruments fall without resistance for the first several feet of sediment. It isn't until the instruments are several feet into the sediment that there is enough resistance to stop the device. It is in this upper, cloud-like layer that the zooplankton find refuge during the day. The zooplankton, then, are largely unavailable to the fish. This is desirable but it would be even better if the small fish were culled. If there were more large fish and fewer small fish, the Lake would be safer from unwanted changes in algae, zooplankton, and weeds. Large predator fish were not captured and do not seem present in good numbers. There are reports of several species, but none were observed during this study, and usually, largemouth bass and pike are noted if they are at all abundant. Predator fish are necessary in a healthy lake to keep the small fish in control and help the system to be more stable. Weed growth may or may not be a problem in lakes. It depends on the type of weed, how densely it grows, and how wide spread it is. Weeds do furnish shelter and food for some insects and give a protected place to spawn for some fish. But they can also interfere with the desirable aspects of the lake by allowing too much shelter to small fish, by robbing the lake of oxygen when the weeds die, and by interfering with human uses of boating, fishing, and swimming. Rooted weed growth in Little Island Lake was very minimal during the year of study. By late season, there were a few patches of Potamogeton species in the deeper waters of the west bay and some scattered Elodea, but nothing that would adversely affect the Lake. Nutrients are available in the sediments for weed growth and there is plenty of light at that level, but it is the flocculent nature of the sediments that prevents suitable rooting of the weeds. The weeds cannot grow if their "soil" is constantly shifting. It is desirable if this low level of weed growth continues. The sediments of the Lake are very flocculent, very thick, and are where most of nutrients reside. In most lakes, the phosphorus level is highest in the first few feet of sediments. Little Island Lake follows this trend with the upper sediments containing 640 mg/Kg of phosphorus and the lower sediments containing 120 mg/Kg phosphorus. This is enough phosphorus to help land plants grow if it were removed and placed on the land, but it is not concentrated enough to be called a fertilizer. Commercial fertilizers contain 50 to 100 times more phosphorus and even cow manure contains twice the phosphorus of the upper Lake sediments. We did test the sediments on rye seed in potting soil and found that the plants germinated as well with a mixture of Lake sediment and native soil and grew somewhat faster for the first two weeks than control plants in non-treated soil. The sediments also showed variation from bottom to top in the kinds of materials present. The oldest sediment near the bottom was rich in certain diatoms that disappeared from the mid and upper sediments. There were no fibrous weed remains in the deep sediments but these remains were found in the upper sediments. Pine pollen was rare in the deep sediments and became more prevalent in the upper half. These are indicators of a change in environmental conditions over the 8,000-year history of the Lake. They document that the Lake has changed from a nutrient poor condition early in its history to a nutrient rich situation in recent decades. The overview of the biology of the Lake, then, is as follows: The algae types and amounts are generally good most of the time, but the Lake does show signs of changing to an undesirable blue-green algae dominance. The algae is kept in check by a very healthy population of zooplankton that feeds at night and finds shelter in the flocculent sediments during the day. There are too many small fish and not enough large predator fish for a healthy fishery and to buffer the Lake against unwanted change. Rooted weeds have difficulty growing because of the flocculent and shifting sediments, which is a desirable situation. DISCUSSION AND RECOMMENDATIONS Little Island Lake needs action in three categories to protect and improve the Lake: increase the water volume, restrict the amount of incoming phosphorus, and promote the biological balance. All three items are of very high priority because the Lake is in a rather precarious water quality condition. The volume of the Lake needs to recover to what is considered normal levels. The average Lake depth (volume/area) in 2001 was only two feet and the deep spot was only eight feet. That is not enough depth to prevent fish kill in a severe winter. It is not enough depth for proper fish protection and reproduction. It is not enough depth to protect against undesirable change should any of the present desirable aspects deteriorate. And it is hardly enough depth for safe recreation. Many studies have made the connection between lake quality and depth, with the better quality lakes having greater average depth. Little Island is in desperate need of greater volume and depth. Dredging the sediments is not considered feasible at this time. Although there is plenty of sediment that could be removed with good effect, doing so would be dangerous to the continuance of the Lake itself. The sediment acts as a sealant against the sand bottom and does not allow the water to move down through the bottom much like a clogged kitchen strainer holds water whereas a clean one does not. Dredging too deep could open holes in this sediment seal and the water would exit the Lake even faster than it does now. It is recommended that, for now, the sediments be left alone unless some type of top sediment skimming device could be found to reduce the top few feet only, and in a controlled manner. The exception is the northeast channel. Since this is an groundwater input area, keeping this area open is beneficial to the Lake. Water well augmentation is also not considered feasible. A high capacity well in the upper watershed would speed the water to the Lake but would diminish the water available in the future. A well in the immediate Lake area would have a similar effect. It would pull water down from the Lake only to pump it back into the Lake. A well downstream in the groundwater watershed pumping water back up into the Lake may have some positive affect but it would have to be a considerable distance west of the Lake and the withdrawal of groundwater could affect the Au Gres River springs and tributaries. It would also take a considerable amount of water to make a difference. The well would have to make up about 40 million gallons over the summer to be effective. A lakeshore-sealing project is recommended to help restore the depth of the Lake. The evidence on hand shows that about two thirds of the water leaving the Lake in a single year leaves via the groundwater on the west side of the Lake. It is further suspected that the vast majority of this exit water leaves through the upper foot or two at the rim of the Lake on the west side. It follows that if this porous area could be sealed with a fabric or clay, then the water would be retained and the Lake would rise. The envisioned procedure would be to have a backhoe with a wide bucket move along the Lake shore pulling back the sand from about a foot below the low water level and about a foot deep into the sand. A crew would roll the fabric into this shallow depression and the machine would replace the sand over the top. This fabric would lie about a foot under the sand all around the west side of the west bay from a foot below the low water level to about two feet from the upper water level. This layer of fabric would severely limit the water exiting the Lake from this location, thus bringing the water level up. The fabric would extend only to within about two feet of the high water mark so that the water would then flow over the top and exit the Lake when it reached its more proper height. If the Lake was in danger of rising too far, some of the fabric could be removed. Although the present study was designed to find the problems with the Lake and present solutions, it was not intended to detail every aspect of the potential actions. It is recommended that a more detailed study by a hydrology firm be implemented around the Lake to further pinpoint where the water leaves the Lake, how much area would have to be covered with the impervious material, and what the expected result would be. From this information, it would then be decided on how to proceed with the lakeshore-sealing project. Since it is our recommendation that a more detailed study of the effect a lakeshore-sealing project would have on, not only Little Island Lake, but also the surrounding lakes, we contacted NTH Consultants, Ltd., a geotechnical and environmental firm that specializes in this type of project. We have been in contact with them and have forwarded a draft copy of the final report to them for review and for estimating services they would recommend be completed before such a project would be implemented. We have attached their proposal, which includes a Scope of Work and estimated fees as Appendix 2. Once you have had a chance to read and review NTH's proposal, we are willing to schedule a meeting between ourselves, Aquatic Services, NTH, and the Lake Board to discuss the scope and fees if this is an option you would like to explore further. Please contact the Bay City office of Wade-Trim at 989.686.3100 and we will make the necessary arrangements for a meeting. Reducing phosphorus input is very important to Little Island Lake. It is realized that all the sources of phosphorus cannot be controlled to the extent desirable (Exhibit 4) but every effort should be made to limit the amount of input. Every pound of phosphorus that enters the Lake results in added three tons of muck. Excess phosphorus is also the trigger that often shifts the algae to the noxious blue-green type. Controlling this nutrient will help preserve the good qualities of the Lake. Tree leaves that work their way into the Lake are probably one of the larger contributors of phosphorus in the "dry fall" category. It is recommended that a leaf composting system be initiated. Leaves make excellent compost that can be used around the home to enhance the soil. The composting area should be located, if possible, over the crest of the hill that forms the immediate watershed to the Lake (e.g. across the road) so that no rain runoff from the site could enter the Lake. It would defeat the purpose if the nutrients from the decomposed leaves found their way back into the Lake. Leaf composting takes time and some attention, but several pounds of phosphorus could be prevented from entering the Lake if the residents were diligent about raking and removing the leaves. Perhaps incentives of raking help or transport equipment could be made available through the associations or Board to help make the effort a little easier. The exact procedure for composting is available in books and it is suggested that a community that runs a composing program be contacted for additional information on how to best accomplish the composting. The City of Midland, for example, has conducted a successful composting program for many years. Septic tank and drain field maintenance is important to the health of the Lake. This nutrient source is difficult to detect, but all Lake residents should be concerned and should maintain their own septic systems to a high degree. Pumping the tanks on a yearly basis is a good starting point. When a new field is needed, it should be placed as far from the Lake as possible. Clay materials adsorb phosphorus very well and if upgrade of a field is necessary, it would be wise to mix a little clay into the soil downstream from the drain field. The County Health Department will have additional information on this subject. Be aware that the purpose for lake residents is not just that the septic system works, but that it also stops dissolved phosphorus from reaching the Lake. There were large numbers of geese on the Lake during the year of study and these animals are detrimental to the Lake. Geese feed regularly outside the Lake area and bring in and deposit phosphorus in large quantities. It is estimated that the existing goose population brings in several pounds of phosphorus per year. Hunting should be maximized. The DNR may have suggestions for discouraging their presence in the off-season times. Surface applied phosphorus fertilizers should not be used on the Lakeside of the road. Although the soils are quite porous, heavy rains and spring runoff could wash the fertilizer into the Lake if it is not yet taken up by the plant life. A test of the native soil found adequate supplies of phosphorus in the soil to grow most plants; about 400 mg/Kg. Trees are sometimes fertilized in the fall to help maintain growth and health. If this is done, it should be done using a subsurface injection method to limit the possibility of any runoff. Overland runoff is a large contributor of phosphorus in many lake watersheds, but not in the Little Island Lake watershed. The soils are porous and the surface grades are not particularly steep into the Lake. We found little evidence of runoff and it is imperative that it remain that way. Any new construction should be done very carefully with full erosion protection systems in place both during and after construction. No new surface drainage sources should be allowed, ever. Surface drainage has been shown time after time to be very detrimental to lake quality. The nutrient loading from these sources is heavy and it usually comes at opportune time for algae growth during the summer growing season. Do not allow surface runoff to reach the Lake. The flocculent nature of the sediments and benefit this has on the Lake ecology has been described in earlier sections of this report. Much of this condition is natural, a factor of the water chemistry and the nature of the sediment particles. However, it is recommended that boat use be encouraged to help keep the particles stirred and in a loose state. A passing boat creates a turbulence several feet below the propeller and this action will help to "kick up" the loose sediment for a few minutes before it settles back to the bottom. This action will help to keep the sediments loose to provide shelter for the zooplankton, create a lack of foothold for the weeds, and help keep the phosphorus attached to the sediments. This condition and recommendation is unique to Little Island Lake. It is extremely important that the fishery in Little Island Lake be modified to keep the Lake quality high and provide more stability to the system. This is done by returning predator fish when caught, by stocking predator fish, and by removing panfish. Again, the food chain is: predator fish eat the small fish so that the small fish do not eat all the zooplankton which keep the algae in check so that the Lake water stays clear and clean. This may seem like a round about way of getting clear water, but it has been shown to work the world over on all kinds of lakes. Even recent journal articles (Tessier 2001) do not dispute the effectiveness of this food chain manipulation but are only interested in understanding it to a greater degree. The first recommendation on the food chain item is to implement at the local level a volunteer, self imposed fishing "regulation" that encourages the return of predator fish. Pike, musky, bass, walleye, and dogfish are all effective fish eaters. These should be returned to the Lake when caught. It is now common for fishermen to carry cameras so they can take pictures of their bragging size fish and use the photos as proof of their accomplishment and good times rather than the fish itself. For truly trophy size fish, there are artificial wall mounts that can closely approximate the fish that was returned to the water if the length and girth are measured and a photo taken. A phrase that is beginning to catch on is "A fish is too valuable to be caught only once". That is especially true for the predator fish of Little Island Lake. They need to be returned to do their part to keep the water clean and fishable into the future. We are also recommending that the predator fish population be augmented. Two-year-old walleye would be the first choice of stocked fish although northern pike and musky would also be effective. In fish stocking, much depends on availability and cost, so this recommendation is flexible. The concept is this: add a known predator fish on a yearly basis in a size large enough that they can be effective in eating minnows and small panfish in the same year. We cannot be certain that these fish will survive all the winters, so it should be viewed as a water quality maintenance effort, not a stocking for fishermen. The fish supplier can help with the details. The third item in food chain manipulation is the removal of small fish. The bluegill and perch are too plentiful for the available food supply and, thus, are stunted. The predator fish will do most of the work of bringing the small fish under control but anything man can do to help will speed the process and help make the Lake more stable. All small (less than about 6 inches long) panfish should be removed when caught. They should be removed from the Lake itself, not just killed and returned, so that their nutrients are also removed. There is no need for concern that the panfish will be depleted. Both bluegill and perch reproduce at impressive rates so there will always be replacement fish. What is needed is to reduce their numbers so that the fewer remaining fish will have enough food to grow quickly into catchable and edible fish. If after a few years of the returning and augmenting the predator fish, the panfish are still undersize, then we recommend looking into electro-shocking removal of small fish. This is where a special generator is placed on a pontoon boat with probes that reach out front into the water. The electrical current dispersed into the water shocks the fish temporarily and they float to the surface where they are netted. The desirable fish can be left in the Lake without harm but the stunted fish can be removed. In a lake as shallow as Little Island, this could be effective. A MDNR permit would likely be needed and the operator may need special training on the equipment but it would be worthy of further investigation if progress is slow in getting the fishery in better balance. The electro-shocking removal would have to be done several times a year to be effective. SUMMARY OF RECOMMENDATIONS All of the improvement measures should be pursued as quickly as possible. Little Island Lake is in a precarious water quality state and needs action to remain a viable resource. In summary, the recommendations are: 1. Implement a lake shore sealing project once further hydrology data shows where the best placement would be. 2. Set up a leaf composting program for the Lake-side residents and encourage its use. 3. Encourage septic tank and drain field maintenance in cooperation with local service companies and the county health department. 4. Discourage the geese from using the Lake. 5. Discourage the use of phosphorus fertilizers within the immediate watershed. 6. Allow no new surface runoff to enter the Lake. 7. Encourage power boat use of the Lake to keep the sediment stirred. 8. Promote the return of predator fish. 9. Stock predator fish on a yearly basis. 10. Encourage anglers to remove all the small fish they catch. 11. If stunted panfish are still a problem in three to five years, look into electro shocking for the removal of panfish. Exhibits Appendix 1 Little Island Lake Water Quality Measurement Little Island Lake Water Quality Measurements Site #1 (deep spot in west bay) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 Dissolved oxygen (ppm) 10.4 pH (standard units) 8.2 8.4 Alkalinity (mg/l total) 100 75 Conductivity (umhos) 210 130 Total Phosphorus (ug/l) <10 Total Nitrogen (ppm) 0.53 Phytoplankton (cells/ml) 880 1200 7400 81 Zooplankton (number/l) 82 85 602 1455 Zooplankton (ave. length mm) 0.61 0.32 0.28 0.30 Phytoplankton, 5/30/01, dominated by Coelastrum, sub-dominate Anabeana 7/2/01, dominated by Chroococcus, sub-dominate Microcystis 8/15/01, dominated by Microcystis, sub-dominate Coelastrum 9/28/01, dominated by Chroococcus, sub-dominate Anabeana Site #2 (northeast of island) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 Dissolved oxygen (ppm) 11.4 pH (standard units) 8.0 8.3 Alkalinity (mg/l total) 82 83 Conductivity (umhos) 115 167 Total Phosphorus (ug/l) <10 10 Total Nitrogen (ppm) Phytoplankton (cells/ml) 71 479 Zooplankton (number/l) Zooplankton (ave. length mm) Phytoplankton, 4/17/01, dominated by Dinobryon, sub-dominate Synedra Site #4 (overflow from Round Lake) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 Dissolved oxygen (ppm) pH (standard units) 7.3 Alkalinity (mg/l total) 70 Conductivity (umhos) 97 Total Phosphorus (ug/l) <10 Total Nitrogen (ppm) Site #5 (groundwater 30 ft from channel in NE corner of Lake) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 pH (standard units) Alkalinity (mg/l total) Conductivity (umhos) 125 Total Phosphorus (ug/l) 320 Total Nitrogen (ppm) Site #6 (groundwater 20 ft from north central Lake) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 pH (standard units) Alkalinity (mg/l total) Conductivity (umhos) 55 Total Phosphorus (ug/l) 630 Total Nitrogen (ppm) Site #7 (groundwater 20 ft from west end of Lake) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 pH (standard units) 7.0 Alkalinity (mg/l total) 52 Conductivity (umhos) 78 Total Phosphorus (ug/l) Total Nitrogen (ppm) Site #8 (groundwater 20 ft from west end of Lake, south of #7) Parameter 4/17/01 5/30/01 7/2/01 8/29/01 9/28/01 pH (standard units) Alkalinity (mg/l total) Conductivity (umhos) 150 Total Phosphorus (ug/l) 1300 Total Nitrogen (ppm) Site #9 (groundwater 15 ft from east central Lake) Parameter 4/17/01 5/30/01 7/2/01 8/15/01 9/28/01 pH (standard units) Alkalinity (mg/l total) Conductivity (umhos) Total Phosphorus (ug/l) 570 Total Nitrogen (ppm) Appendix 2 NTH Consultants, Ltd, Proposal, Scope of Work, and Estimated Fees James C. Lillo, P.E. December 11, 2001 Wade-Trim Proposal No.: P-20011717-F 3933 Monitor Road Bay City, Michigan 48707 RE: Proposal for Preliminary Engineering Feasibility Study Little Island Lake Water Level Management Options Iosco County, Michigan Dear Mr. Lillo: NTH Consultants, Ltd. (NTH) is pleased to submit this proposal to provide engineering consulting services for the above-referenced project. This proposal was prepared based on information you provided during our meeting on November 30, 2001, and our subsequent telephone conversations. Little Island Lake is located in Section 35, Plainfield Township and Section 2, Grant Township, Iosco Township, Michigan. The lake is one of a group of eight small inland lakes approximately 8 miles northwest of Tawas City, which is located on the north shore of Saginaw Bay. We understand that the water level elevation of Little Island Lake has declined by as much as 3 feet over the last several years. Based on a preliminary review of regional topographic maps, Little Island Lake and the adjacent lakes appear to be located in the area of a surface water divide. The individual lakes, although located in close proximity, may be situated in different watersheds. At this point, we do not know whether the adjacent lakes have dropped similarly to Little Island Lake. We understand that an ecological study of the lake is currently being completed by a limnology consultant, Aquatic Consulting Services (ACS). Evidently, their study included installing a limited number of shallow monitoring wells by hand near the lake to develop information on groundwater conditions. Drilling information from these wells indicated that the near surface subsoils consist of sand to the maximum depth penetrated (e.g., approximately 6 feet). No other information on local geology is available. Based on our conversation, the preliminary results of the ACS study suggest that Little Island Lake may be losing water through groundwater seepage to one of more of the adjacent lakes. The preliminary information is not clear whether ACS believes the lake level decline is due to an increase in groundwater seepage or due to a decrease in water flowing into the lake. The full report by ACS is expected to be available in about 3 to 4 weeks. PURPOSE & SCOPE OF WORK The purpose of our proposed study is to develop and evaluate engineering alternatives to restore and maintain the surface water level in Little Island Lake. The following sections describe our proposed scope of work, schedule, and estimated fees. Task 1: Review of Existing Hydrogeologic Information As an initial task, we propose to review the ACS report and other regional hydrogeologic information that may be available, such as geologic maps, topographic maps, or hydrogeologic reports. Our review will also include records of water supply wells installed in the vicinity of the project site along with other materials that may be available from the local health department, Mighigan’s Geological Survey, and other possible sources. Based on information provided from these sources, we will attempt to determine the approximate depth and thickness of underlying geologic strata in the area. We will also try to characterize the regional groundwater conditions (i.e., confined/unconfined), groundwater flow direction, local groundwater recharge and discharge zones, and the possible hydraulic connection between groundwater and local surface water features. We will also contact personnel from the local environmental health department and/or drain commission to determine their knowledge of lake levels and groundwater conditions in the area. The results of this task will be used to establish Little Island Lake’s relationship within the regional hydrogeologic regime and to assess the likelihood that groundwater seepage is a significant factor affecting the lake level. This information will also be used to confirm our proposed approach for the on-site field investigation, which is described below. Task 2: Field Investigation To evaluate the subsurface conditions in the vicinity of Little Island Lake, we propose to drill a series of soil borings and install observation wells at four locations around the perimeter of the lake. The approximate proposed locations of the borings/wells are presented on the attached Plate 1, Site Location Map. As shown, wells will be placed between Little Island Lake and each of the three adjacent lakes (OW-1 to OW-3) and at one location believed to be hydraulically upgradient (OW-4) of Little Island Lake. The purpose of these borings/wells is to develop information on the subsoils at least as deep as the lake bottom and to attempt to establish the direction of groundwater flow around the lake. In addition, the wells will attempt to establish if hydrogeologic conditions exist that could allow for an engineered artesian recharge of the lake. The proposed locations of the wells are subject to physical accessibility and consent by landowners. Following completion of the drilling and well installation activities, a land surveyor will establish the locations, ground surface elevations, and top of casing elevations of the observation wells. For the purpose of this proposal, we have assumed that this service will be provided by Wade-Trim Associates. The surveyor will also establish staff gauges in the nearby surface water features, at the approximate locations shown on Plate 1. We will measure groundwater levels in the new and existing observation wells at the site and surface water levels at the staff gauges on at least three occasions over a period of approximately four weeks. We also plan to perform in situ permeability (“slug”) tests in the four observation wells. The purpose of these tests is to develop estimates of the hydraulic conductivity of the shallow water-bearing soils. This information will be used to estimate the seepage rate and groundwater flow velocity within these shallow soils. Slug testing consists of measuring the response of the water level in the well to an “instantaneous” change from its static condition. Usually, the water level is changed by inserting a known volume of water (i.e., a “slug”) or a length of 1-inch diameter PVC tubing filled with sand and sealed at both ends. The slug is quickly inserted into the well, thereby creating an "instantaneous” rise in the water level in the well. An electronic pressure transducer and data logging device will be used to record changes of water level in the well as it recovers to the original static condition. We generally repeat the test by quickly removing the slug from the well, thereby creating an "instantaneous" lowering of the water level in the well and measuring the recovery of the water level in the well to the original static condition using the same electronic data logging device. Task 3: Interpretation and Analysis At the completion of the field investigation, we will analyze the data to assess the factors that are likely affecting the lake level. Based on this analysis, we will develop a number of possible strategies to restore and maintain the lake at historic levels. On a preliminary basis, possible approaches may include installing a barrier wall to restrict groundwater seepage, augmenting the lake level with wells, or a combination of these strategies. We will then evaluate the feasibility of the various options on a preliminary basis. The general criteria for this evaluation will include constructability, effectiveness, reliability, and relative cost. We note that our assessment is designed to assess the general feasibility of several options for raising the lake level. If the results appear to be favorable for one or more of the options, additional drilling, testing, and/or continued groundwater level measurements may be needed to confirm these results and to provide sufficient information to design the actual remedy. Task 4: Report Preparation After analyzing the data, we will prepare a written report summarizing our investigative methods, results, and feasibility evaluation, including concept sketches of potential solutions. In addition, we will estimate approximate cost ranges to implement the conceptual designs. If requested, we can also provide preliminary results verbally. We are also prepared to attend a meeting with Wade-Trim and your client to present and discuss our findings. However, we have not included any meetings in our fee estimate. PROFESSIONAL FEES & GENERAL CONDITIONS Charges for performing this work will be made in accordance with our current Fee and Rate Schedules FS-ENG-2 and FS-ER-1, dated 3/2001. General terms and conditions will be in accordance with the Standard Wade-Trim-NTH Subconsultant Agreement, a copy of which is attached. On the basis of the scope of work defined in this proposal, we have developed an estimate of our fees for each of the individual tasks described above. Should additional work beyond the scope outlined in this proposal be requested by you or required by field conditions, we will contact your office with an estimate and obtain your permission prior to performing such services. Our anticipated fees are listed below. Task Description Estimated Fee Task 1: Review of Existing Hydrogeologic Information $ 1,800 Task 2: Field Investigation ,900 Task 3: Interpretation and Analysis $ 2,800 Task 4: Report Preparation $ 2,400 TOTAL ,900 Finally, we point out that technical assistance is available to local governmental agencies from the U.S. Army Corps of Engineers (USCOE) for projects involving restoration or maintanence of surface water features and ecological restoration. The Little Island Lake project may be eligible for such assistance, which can reduce some costs associated with investigation, design, and construction of remedial measures. Funds for projects occurring in 2002 have already been designated. However, funding may be available for projects beginning in 2003. If you are interested in pursuing this type of alternative funding and cost sharing, we would be happy to discuss the requirements and/or assist in the application process. We appreciate the opportunity to present our proposal for your consideration. Please indicate your acceptance of this agreement by signing below and returning a signed copy for our records. The executed copy will serve as our contract and authorization to provide engineering consulting services. If you have any questions or need additional information, please feel free to call us at (248) 553-6300. Sincerely, NTH Consultants, Ltd. Alan C. Erickson, P.E. Fritz J. Klingler, P.E. Senior Project Engineer Vice President ACE/FJK Attachments ACCEPTED FOR WADE-TRIM BY: PRINT NAME: DATE: Appendix 3 Little Island Lake References American Public Health Asso. & American Water Works Asso. "Standard Methods for the Examination of Water and Wastewater" 20th Edition 1998 Carlson, Robert E. “A Trophic State Index for Lakes” Limnology and Oceanography Vol 22 No. 2 March 1977 De Robertis, A., J. S. Jaffe, and M. D. Ohman "Size-dependent visual predation risk and timing of vertical migration in zooplankton" Limnology and Oceanography Vol. 45, No. 8 2000 Dillon, P.J. and Rigler, F.H. “A Simple Method for Predicting the Capacity of a Lake for Development Based on lake Trophic Status” Journal of the Fisheries Board of Canada Vol 32 No. 9 September 1975 EPA “Wastewater Management in Rural Lake Areas” Final Generic Environmental Impact Statement January 1983 Garn, Herbert, Harry Parrott "Methods for Classifying Lake Condition, Determining Lake Sensitivity, and Predicting Lake Impacts" Hydrology Paper 2, March 1977 U.S. Dept. of Agriculture Hakanson, Lars "On the principles and factors determining the predictive success of ecosystem models, with a focus on lake eutrophication models" Ecological Modeling 121 (1999) 139-160 Jones, R.A. and Lee, G.F. “Septic Tank Wastewater Disposal Systems as Phosphorus Sources for Surface Waters” JWPCF Vol 51 No. 11 November 1979 McGurrin, Jim Lake height measurements May 1999 – November 2001 Personal communication King, Darrell L. “Lake Eutrophication: Definition and Causes” in Conference on Inland Lake Eutrophication: Causes, Effects and Remedies Many 1979 Larsen, D. P. and H. T. Mercier "Lake phosphorus loading graphs: An alternative" National Eutrophication Survey, working paper No. 174, 1995 Lhlgren, Ingemar, Tom Frisk and Lars Kamp-Nielsen "Empirical and theoretical models of phosphorus leading, retention and concentration vs. lake trophic state" Hydrobiologia 170: 285-303, 1998 McGurrin, Jim Lake Level Measurements Personal communication 2001 Mills, E. L. and Albert Schiavone, Jr. "Evaluation of fish communities through assessment of zooplankton populations and measures of lake productivity" North American Journal of Fisheries Management 2:14-27 1982 Moss, Brian, Jane Madgwick, Geoffery Phillips "A Guide to the Restoration of Nutrient-enriched Shallow Lakes" WW Hawes, UK 1997 North American Lake Management Society "Lake and Reservoir Management: Practical Applications" Proceedings of the Fourth Annual Conference 1984 Phillips, Geoff, et al "Practical application of 25 years' research into the management of shallow lakes" Hydrobiologia 395/396: 61:76, 1999 Reckhow, K. H. "Quantitative Techniques for the Assessment of lake Quality" U. S. EPA Report No. EPA-440/5-79-015 January 1979 Reckhow, K.H. "Uncertainty analysis applied to Vollenweider's phosphorus loading criterion" JWPCF Vol. 51, No. 8 Aug 1979 Stauffer, Robert E. “Relationships Between Phosphorus Loading and Trophic State in Calcareous Lakes of Southeast Wisconsin” Limnology and Oceanography Vol 30 No. 1 January 1985 Tessier, Alan and Elena Bizina "Grazer-resource interaction in the plankton: Are all daphniids alike?" Limnology and Oceanography, Vol. 46, No. 7 Nov. 2001 U.S. EPA "Wastewater Management in Rural Lake Areas" Final-Generic Environmental Impact Statement January 1983 Walker, W. W. Jr. "Some analytical methods applied to lake water quality problems" Ph. D. Dissertation, Harvard University, 1977 Wetzel, Robert G. Limnology Second Edition Saunders College Publishing 1983