2002 Aquatic Plant Survey
Report on Aquatic Plant Survey of Bungay Lake and Management Recommendations
To: Scott Freerkson; Bungay Associates, Inc.
From: Gerald Smith; President/Aquatic Biologist, Aquatic Control Technologies
This report presents the results of an aquatic plant survey performed at Bungay Lake on November 20th, 2002. You were kind enough to spend the afternoon with me to perform this survey and share with me your extensive knowledge of the lake and history of management activities undertaken by the Lake Association.
At the time of our inspection the lake level had been lowered about 2-2.5 feet from what I understand would be its normal, early summer elevation. We inspected the lake from a small boat by travelling around the entire shoreline of the lake (both the main lake and Little Bungay Lake).
Using a "grappling rake" and Aqua-Vu Underwater Camera System, I identified the different types of aquatic plants and produced the attached map showing the major plant groups or assemblages. While several of the plant species had "died-back" significantly from what would normally be seen during the summer, there were still enough remains of these plants for me to see in order to get a good picture of the overall plant community.
Our last similar plant survey had been performed in September 1996 with the plant distribution briefly checked again in August 1996 when our Biologist's collected water samples for chemical and physical analyses.
The types of plants found recently at Bungay Lake have not changed significantly from these prior surveys. In approximate decreasing order of abundance, I observed the following plants.
wild celery or tapegrass (Vallisneria)
clasping-leaf pondweed (P. perfoliatus or P. richardsonni)
fernleaf or robbins pondweed (P. robbinnsii)
American elodea (Elodea)
variable watermilfoil (M. heterophyllum)
white or fragrant waterlily (Nymphaea)
yellow waterlily or spatterdock (Nuphar)
View Actual Pictures From Collection Day
I'd say the overall pant growth appeared to be "modestly" more abundant than what I remember from our inspection in 1996. Again, I defer to you people whom have lived on the lake for many years but an overall increase in plant growth is what struck me.
Secondly, we are now seeing more of the invasive/exotic milfoil and fanwort throughout the lake but more so an increase in the fanwort. Neither species is yet widely distributed but there is definitely more fanwort now, throughout the northern portion of the main lake and along the northwest shoreline, than I remember or show on our plant map from 1996.
Never the less, given the invasive characteristics of milfoil and fanwort, I'm surprised these two plants have not spread throughout the lake even more. The fanwort was observed growing to a depth of about 7-8 feet or about 9-10 feet when the lake would be at its normal full level or elevation.
Tapegrass and claspingleaf pondweed were the two most common plants found throughout the main lake. The tapegrass had senesced (died-back) for the winter but the bottom was strewn with the decomposing remains of this plant. Tapegrass is a native plant that provides good habitat for fish and food for different types of wildlife. Rarely do we see it reach densities that are problematic to recreational uses such as at Bungay Lake.
Clasping-leaf pondweed was also common to abundant throughout much of the lake, along with Robbins pondweed. Claspingleaf pondweed will grow in high densities and reach the water surface in depths of about 6-7 feet at Bungay Lake.
Robbins pondweed tends to remain low to the bottom and rarely becomes a nuisance. In fact Robbins pondweed is one of the more desirable plants, since it acts like a "mulch" and helps to out -compete taller plants.
Coontail was also frequent to common throughout the main lake, more so in the northern portion of the lake. Coontail was often mixed -in with growth of elodea, another common and native submersed plant.
In deeper waters, a low growing macro-alga called stonewort (Nitella) formed a thick carpet on the pond bottom. Like Robbins pondweed, rarely is Nitella a problem.
In Little Bungay Lake, submersed fanwort was widely distributed with lesser amounts of variable milfoil. Dense and sizable patches of floating-leaf smartweed still remained. Remnants of white and yellow waterlilies were also observed. Purple loosestrife, another invasive emergent plant, fringed a good portion of the shoreline.
View Plant Distribution Map
We understand the overall goal of the Association is to manage the lake for recreational pursuits (i.e. swimming, fishing and boating) while preserving the wildlife and fisheries habitat.
We also understand that Hydro-Raking is the only organized weed control technique that has been carried out on the lake in recent memory. Last year's Hydro-Raking program totaled about 40 hrs., and was performed in mid/late May. Raking has generally been performed once every two years, with most participants taking just one hour of time. You mentioned that some participants this year were questioning whether this technique was now as effective as it might have been in prior years. Lowering the lake level during the fall and winter some 2-2.5 feet has been practiced for many years. The lake level is not lowered so much for weed control as it is to allow homeowners to repair walls, rake beach fronts and allows for a lower lake level in the event of heavy fall rains and to mitigate against ice damage in the spring.
Lake Level Drawdown:
Lowering the lake's water level significantly (say ~6-8 feet) could provide a relatively low cost and effective method to control the fanwort and milfoil throughout the main lake. The channel between Little Bungay and the main lake would need to be dredged and deepened considerably before the Little Lake could be lowered much more than it is currently.
We understand the dam has recently been rebuilt and the new dam would allow you to gravity lower the main lake level by 8 feet or more. Most of the costs associated with drawdowns are typically for permitting and monitoring.
Both plants have root systems (rhizomes) that are normally sensitive to the combined effects of freezing and drying during the fall and winter months. In fact fanwort in particular, is generally found to be one of the most sensitive plants to drawdown. Normally, drying and freezing is required for a sustained period of 6-8 weeks in order to destroy these reproductive structures.
Plant control may not be attained during all years of drawdown, given variations in climatic conditions, such as an early insulating snow-fall, a mild winter or excessive rain, in which case the reproductive structures may not be destroyed.
There is some potential for drawdown tolerant plants to increase after drawdown. Tapegrass and one or more species of pondweed could show some increase post-drawdown but the potential control of milfoil and fanwort may make this a worthwhile approach anyway, in our opinion.
Most of the milfoil and fanwort in the main lake is found in water depths of between 4 and 8 feet, therefore, a drawdown of at least 6 feet and preferably 8 feet is necessary for this to be an effective technique at Bungay Lake.
There are a number of legitimate concerns regarding drawdown that need to be explored before deciding to move ahead with this technique.
First off is determining the time for the lake to refill in the spring, since the lake does not have a terribly large watershed. This can be determined fairly readily by constructing a hydrologic (water) budget for the lake and its watershed, that examines the time and flow rate required to lower the lake along with the time for lake re-fill. Calculations can be performed to for a year given "normal" rainfall and for drought years. Drawdowns typically begin during early October with the lake remaining lowered until early or mid-winter. The final schedule for drawdowns are guided by weather patterns and the projected time to refill the lake by late March, which marks the start of spawning period for certain species of fish.
We strongly recommend that a phased approach be followed for lakes that are being drawn-down for weed control for the first time . This means that if your looking to eventually achieve a maximum drawdown of say eight feet, you develop a plan of drawdown that may span a four year period and perform annual drawdowns in progressive two foot intervals accompanied by monitoring of the lake's fish and wildlife community, adjacent shallow wells (if any remain) and other environmental parameters.
Where I understand from you that the lake's maximum depth is only about 15 feet, this lack of deeper water could be an obstacle to deeper drawdowns of say 6 or 8 feet, due to valid concerns regarding potential fish mortality. It would be very helpful if I could look at a bathymetric (depth) map for the lake, if you have one available.
A Feasibility Evaluation of drawdown to address the concerns expressed above and other potential effects ( ie aesthetic impact; potential interference with winter uses of the lake, etc) should be performed if the Association wants to pursue this approach further.
The estimated cost for these investigations should be in the range of $5000-$10,000, providing you have a reasonably accurate map of water depths for the lake. While we do some of this evaluation and design work ourselves, it's not our forte and we'd recommend you hire a professional engineering/environmental consulting firm. We can recommend a couple of companies to you whom have performed a number of similar assessments for other lakes.
Chemical (Herbicide) Treatment:
Herbicide treatment is the most common approach in MA and across the country to control invasive and nuisance aquatic vegetation. In MA alone, some 150 or more ponds/lakes are chemically treated each year in more than 75 cities and towns. We perform about two-thirds of all chemical treatment work in MA.
The only aquatic herbicide effective on fanwort is Sonar (fluridone). Sonar works best on whole-lake applications, whereas it is highly soluble and tends to dilute out of smaller treatment areas. Within just the past year, the manufacturer of Sonar (SePro Corp.) has developed a new pellet formulation of Sonar which has shown some good results for partial lake applications. Sonar works slowly and requires an approximate 40-50 day "contact time" with the plants for effective uptake. Maintaining this contact time can be difficult in coves with significant water circulation or in lakes that have a rapid flow - through or "flushing rate".
The weed situation at Bungay Lake is not that severe and does not warrant a whole-lake treatment program with Sonar at an estimated cost in the range of $50,000-$60,000.
Treatment of Little Bungay Lake and the two northern coves in the main lake are warranted to provide some relief from the fanwort and to help retard the further spread of this invasive plant throughout the rest of the lake. Treatment of the far eastern cove in the main lake would also be recommended but it not as critical as these other areas since it is somewhat more isolated from the main body of the lake. If nothing is done to halt the continued spread of fanwort, we predict it will eventually take over the main lake and create a tremendous nuisance.
It makes sense to be pro-active now, while the plant's distribution is still somewhat limited, the effects of treatment will be less than a whole-lake application and the costs will be less.
The challenge to effective treatment with Sonar at Bungay is the amount of water flow that occurs into Little Bungay and at the head of the main lake where most of the fanwort is found. We would recommend a combined treatment approach using both the liquid and pellet formulations of Sonar. Multiple treatments (one initial treatment and 2-3 booster applications) would likely be required to maintain the required contact period of 40-50 days. The total treatment area is about 35-40 acres and is shown on the attached map. Treatment would commence in late May or June, when the fanwort is actively growing but after the normal higher spring flows have passed.
Prior to treatment, it would be helpful to lower the lake level by about 1-1.5 feet in order to help contain the Sonar in the lake. This lowering would occur only prior to the initial treatment. The culvert between Little Bungay and the main lake could be temporarily sand-bagged to further help contain the chemical in Little Bungay. Sonar's half-life is about 3 weeks in water, not withstanding the Sonar lost to dilution and outflow.
The timing of the booster applications is guided by collecting and analyzing water samples every 7-10 days post-treatment from the treated areas and having these samples analyzed for residual Sonar concentrations. We ( or the Association) send these samples to SePro overnite mail and they typically have the tests run and the results back to us within 1-2 days.
Based on our extensive experience with prior fanwort treatments in MA, we initially target a dose of 15-25 ppb and try and maintain a minimum concentration of 10 ppb for the 40-50 day period. This dose is well below maximum label rate for Sonar of 150 ppb. We would anticipate good control of the fanwort and also the milfoil. If the milfoil was not completely controlled within the treatment areas, we would spot-treat these areas later in July with Reward (Diquat) herbicide.
Sonar will impact and control most of the other plants within the targeted treatment areas. These non-target plants, however, will rebound over the next 1-2 years while typically the fanwort is controlled for generally 3 years or longer.
The total cost for the Sonar treatment program is approximately $25,000-$30,000 plus an estimated $2,000 to permit the project with both the No. Attleboro and Mansfield Conservation Commissions and MA DEP.
Chemical treatment of tapegrass is generally not very effective. We don't have any registered herbicide that exhibits "predictably" good control of tapegrass. We could first perform a "pilot or demonstration treatment" of one cove or shoreline area at Bungay Lake with Nautique - a copper based herbicide which some Applicators have reported good results with on tapegrass.
Estimated costs would be in the range of $3,000 plus permitting, if done in combination with the Sonar treatment program or $5,000 if done alone.
Effective treatment of the claspingleaf pondweed, which along with the tapegrass is the most abundant and problematic native plant can be attained with a combination of Reward (Diquat) and Aquathol K (dipotassium endothal) herbicides.
Treatment costs would run about $400/acre, assuming a minimum treatment area of roughly 10 acres. We can discuss with you the priority shoreline and cove areas for this potential treatment.
View Map of Recommended Treatment Areas
Mechanical cutting and harvesting is an effective means of controlling native plants like tapegrass and pondweed. Harvesting of milfoil and fanwort must be done very carefully so as to collect all fragments to avoid inadvertent spreading of the plant to other portions of the lake from the fragments that escape collection.
Generally, we do not recommend harvesting in lakes that contain milfoil and fanwort. The commercial Harvesters cut to a maximum depth of between 6 and 7 feet. Typically two cuttings per summer are necessary for adequate plant control. Harvesting is simply an annual maintenance strategy and more lakes are getting away from harvesting rather than adopting this management technique. We believe that either drawdown or herbicides offer a better and more economical approach to managing the nuisance plants at Bungay Lake as opposed to harvesting.
The residents at Bungay Lake are familiar with Hydro-Raking. Raking has the advantage over harvesting of removing the plants and some of their roots, along with being able to remove rooted plants to a maximum of 12 feet, where necessary. Longer term control is achieved with raking than simply cutting the plants as with harvesting.
Tapegrass is a difficult plant to effectively rake because the plants are not branched and therefore, they often "slip through" the steel tines of the rake. We've had the same two operators perform the work at Bungay in recent years. Both of these men have been with us for over 15 years, therefore, any decline in the results (effectiveness) of the raking process now being achieved is not a function of a lesser experienced machine operator.
The pondweed species typically grow from seed and may not be up and established when the raking process occurs in mid/late May. If the Association decides to continue with Hydro-Raking in the future, a July raking may prove to be more effective.
Permitting for any of the management techniques discussed above will be required from the local Conservation Commissions in the two municipalities. Filing of a Notice of Intent (NOI) in accordance with the Wetlands Protection Act is required. We assemble a detailed description of the project, discuss alternatives to the action being proposed and examine the project in-light of the wetland statutory interests.
All lake abutters are notified by certified mail and a public hearing on the project is held by the Commissions. If the Commission approves the project, they typically do so with a set of "conditions" of approval. The Town of North Attleboro is a long-time lake management client of ours and we would not expect a problem in permitting chemical treatment with them. We have no experience with the Mansfield Commission.
The cost for us to assemble and file the NOI and attend a public hearing in each community is about $2,000. You should also budget an additional $1,000 for state/local filing fees, certified mailings and other reimbursable expenses. For chemical treatments we also file what's called a License to Apply Chemicals with MA DEP, Office of Watershed Management in Worcester. This is a straight forward permit that we typically obtain given 45-60 days lead time.
Allow at least 90 days lead time for the NOI process. For drawdowns, additional state and federal permits may be required. Permitting costs for drawdown are also likely to be more involved and we suggest budgeting $4,000-$5,000 for the two Conservation Commissions and potentially much greater costs if other state and federal permits are required.
In summary, based on our recent observations, we recommend the Lake Association take a more aggressive approach towards the management of vegetation throughout the lake with a need to focus first on the invasive fanwort and milfoil in Little Bungay and the northern coves of the main lake, along with control of native tapegrass and pondweed in localized, high use areas of the main lake.
A Feasibility Assessment of drawdown should be pursued. Partial lake treatment with Sonar herbicide targeting fanwort and milfoil should be considered along with drawdown. Chemical (herbicide) treatment of tapegrass and pondweed can and should proceed in 2003, on a limited scale to evaluate effectiveness and independent of whether drawdown can proceed or not, since these plant species are likely not to be controlled by drawdown.
1996 Aquatic Plant Survey
Report on Biological Survey of Bungay Lake and Management Recommendations
by Gerry Smith, President/Aquatic Biologist - Aquatic Control Technology, Inc.
This report presents the findings of an Aquatic Plant Survey and Water Testing performed at Bungay Lake with you on September 12th, 1996. The objectives of the survey were two-fold;- one, to continue the data base of water quality testing performed in recent years and two, to examine the aquatic plant community and reevaluate management options to control nuisance vegetation.
Lake Description and Sampling Approach:
Big Bungay Lake has a surface area of approximately 108 acres as measured from a USGS topographic map. Little Bungay shows a surface area of about 18 acres, although probably 50% or more of Little Bungay is now "emergent wetland", rather than an open-water pond. Both lakes are quite shallow. You reported a maximum depth for Big Bungay in the range of 15 feet and roughly 3-4 feet for Little Bungay. The watershed or drainage area to the lake is sizable, mostly located in Mansfield and No. Attleborough but also encompassing smaller areas of Plainville and Foxboro to the north. There are an estimated 150-200 homes on the lake with you projecting that roughly 90% are now occupied year-round. All homes are reportedly on cess pools/septic systems as there is no municipal sewage system that serves the lake area. I understand most homes, however, are on town water.
On the day of our inspection, aquatic plants were surveyed from a boat through visual inspection and by dragging a rake or small anchor while proceeding in a counter-clockwise direction around the entire lake shoreline. The plants were identified in the field and dominant plant types keyed to a map of the lake to show distribution (see attached map). Water samples were collected from the same 5 sites that have been sampled in recent years. These were surface "grab" samples, collected approximately 1 foot beneath the surface. The samples were delivered to a state certified laboratory for analyses of bacteria along with certain chemical and physical constituents. A temperature/oxygen profile was taken near the deeper, central portion of the lake, along with collection of a surface sample for microscopic examination of algae.
Results of the Plant Survey:
Overall, I'd characterize the plant community as moderate to locally abundant in specific areas. Little Bungay is now quite shallow and aquatic plants are abundant throughout. There are two invasive and probably exotic (non-native) plants of concern in both lakes, that are not too wide-spread presently but we would expect them to become more problematic as time goes on. These plants are variable watermilfoil (M. heterophyllum) and fanwort or cabomba (C. caroliniana). The fanwort is thought to have been inadvertently introduced to MA waters through the aquarium industry in the south. We find fanwort to be quite invasive, in some cases dominating a lake's plant community once it's been introduced. The fanwort was found throughout much of Little Bungay that could be accessed by boat and in the northern cove(s) where Little Bungay enters the Big Lake. It was also found in several other areas in the Big Lake most noticeably the southeast cove. Fanwort is a perennial plant that grows fairly slow in the spring but by mid summer is probably approaching the water surface at depths of 4-5 feet. Where fanwort flowers, it produces a white colored flower that protrudes above the water surface, usually in August or September.
The variable milfoil is not too extensive in either Big or Little Bungay. It did not appear to be vigorously growing and was only locally abundant in a few areas and most noticeably in Little Bungay and again in the northern coves of Big Bungay.
Both lakes also support a good diversity of native plants. Tapegrass or Vallisneria is probably the dominant plant along with clasping leaf pondweed (P. perfoliatus). Both plants are desirable when found in recreational lakes in low to moderate abundance. They provide good cover for fish and fish-food organisms (i.e. invertebrates, small crustaceans, etc.) When found in swimming areas however, they can be problematic. Waterlilies including Nympaea, Nuphar and Brasenia were prevalent in some of the shallow coves. Smartweed or Polygonum, a floating-leafed plant, dominated the vegetation throughout the shallower portions of Little Bungay. Throughout Big Bungay, submersed vegetation was found to a depth of 8-9 feet. Beyond that depth there is insufficient light for plants to grow.
While we no longer have our records of our only previous plant survey dating back to probably 1984/1985, it's our recollection that neither fanwort or the milfoil were found at that time, at least in any significant abundance. I remember tapegrass as being the dominant plant. It would appear that the fanwort, first became established in Little Bungay and is working its way throughout the Big Lake. Both fanwort and milfoil reproduce and spread primarily through vegetative fragmentation which is important to know for future management decisions (i.e.; weed control and boating) for the lake.
Water Quality Results:
All 5 sampling sites (see attached map) yielded low densities of both fecal and total coliform bacteria, well below the State's maximum permissible limit of less than 200 for fecal coliform and less than 1,000 for total coliform. The only station that showed any appreciable coliform density was station 1, located on Little Bungay. Stations 2-5 were located on the main lake. Sampling in Big Bungay revealed a pH almost near neutral at 7. 10. Alkalinity which measures the lake's buffering capacity to resist change in pH was 23 mg/l versus 17mg/l in 1995. Such variations are not thought to be significant. The lake is characterized by generally soft water, with low to moderate susceptibility to long-term acidification. To have sufficient data in order to detect subtle changes from year to year, multiple sampling rounds would be needed throughout the year. This one sampling round provides but a "snap-shot" view of lake quality at one point in time. Turbidity measures the amount of light that passes through the sample. Turbidity is effected by colored and suspended particulates including algae, silt/clay particles, detrital (plant) matter, etc. The turbidity of 1.1 ntu is fairly low and indicative of relatively clear water. The Secchi Disk clarity as measured at station 4 was approximately 6 feet. This is fairly good clarity although particles of blue-green algae could be seen in the water. The state requires a minimum clarity reading of 4 feet for accredited bathing beaches. During mid August 1995, we measured clarity at about 7 feet or not much difference from this year.
Microscopic examination of a surface sample collected at station 4 revealed a moderate density of algae dominated by the "blue-green" genera Coelosphaerium and secondly Microcystis. The overall density of algae throughout the water column was probably not that high, however, these buoyant types of algae tend to skew the results.
Phosphorus and nitrogen are the key nutrients that generally limit plant growth in freshwater systems. The total phosphorus concentration was 0.02 mg/l which is fairly low and desirable. Nitrate nitrogen, which is the inorganic form of nitrogen readily available for plant uptake was less than 0.2 mg/l which is also low. Again we reiterate that multiple sampling rounds and locations are needed to make any conclusive statements regarding average water quality conditions throughout the year.
The temperature/oxygen profile taken at station 4, showed a surface temperature of 22c (72f) and was constant to a depth of about 10 feet. Dissolved oxygen was 8.2 mg/l at the surface and declined slightly to 7.6 at 10 feet. This fairly shallow lake is not expected to stratify thermally and is probably well oxygenated to the bottom throughout most of its area. Summer temperature and oxygen levels are fine for supporting a warm water fishery.
Management Alternatives and Recommendations:
Prudent lake management requires continuous and diligent efforts towards shoreline and watershed protection and maintenance. At Bungay Lake, septic system maintenance is probably the largest contributor of nutrients to the lake which can stimulate floating weed and algae growth. Rooted plants derive most of their nutrition from the nutrient enriched sediments. That's why watershed management alone will not deal with or solve rooted plant problems. To focus on weed control alone, however, is inappropriate because the weed/algae growth will only worsen over time if the input of nutrients and sediment entering the lake is not curbed. The Lake Association at a minimum needs to aggressively pursue participation in a septic maintenance program for all waterfront property owners. Routine pumping of systems; water conservation ;and care as what goes into the septic system are very important elements of such a plan.
While we understand the lake presently does not presently experience massive algae blooms, the observation of blue-green algae "clumps" suspended in the water during my inspection, suggests the lake may be at a critical point where just a small addition of nutrients may lead to some serious algae problems in the near future.
Aquatic Vegetation Management:
Based on the assemblage and abundance of vegetation observed throughout the lake, vegetation management is appropriate in some areas. We believe the presence of fanwort and milfoil needs to be carefully monitored for future expansion. The only effective method of "controlling" milfoil or fanwort in areas larger than about 0.25 acres is through the application of USEPA/ MA DEP registered aquatic herbicides. The only herbicide effective on both fanwort and milfoil is a herbicide called Sonar (Fluridone). Sonar would be difficult and fairly costly to use at Bungay, because of the continuos water inflow from Little Bungay.
Chemical treatment is not recommended for the main lake. Weighing the importance of the tapegrass and other plants to maintain a balanced aquatic habitat, large-scale treatment with any herbicide is not recommended. In addition, the dominant native plants (pondweed and tapegrass) are quite resistant to those products that are approved for aquatic use. We chemically treat more ponds and lakes throughout MA than any other company but at Bungay Lake we don't believe chemicals are the most appropriate strategy, other than for dealing with the fanwort or milfoil. Where milfoil and fanwort pose a real threat to the entire lake, such a control program should be funded by the Association and not just the property owners whom live in these areas.
For the continuing maintenance of swim/beach front areas, Hydro-Raking remains the best approach in our opinion. Raking in areas of milfoil or fanwort must be carefully done in order to capture fragments of the plants or not at all. If necessary, we can deploy floating, fragment barriers at an additional cost. It would be best to limit motorboat activity in these areas as well. Residents should be instructed to identify these plants and then informed about minimizing boating activities in such areas and careful mechanized or manual raking of these plants. In areas that have been Hydro-Raked, it will continue to be an annual weed control process although we typically see a reduction in density the following year.
The lowering of some lakes to freeze and control plants during the fall and winter can be an effective and low cost strategy. However, In shallow lake like Bungay, drawdown can have adverse impacts on fish, wildlife, aquatic vegetation, adjacent shallow wells and contiguous wetland areas. Drawdown requires you to drop the body of water 4 to 5 feet for it to be an effective technique for weed control. This would not be practical at Bungay Lake. Scoping out either a drawdown or dredging project for Bungay is well beyond the scope of this survey. Both techniques have some real concerns, however, that need to be thoroughly addressed before deciding to proceed and permits are often required at the local, state and federal level. There are very few, dry -dredging projects of a magnitude the size of Bungay, that are currently proceeding, in view of today's regulatory constraints.
The use of bottom weed barriers may be an option that some homeowners should consider. We sell and distribute a "fine, meshed screening product" called Aqua-Net. It's laid over the weeds and controls the weeds through compression and blocking of light, generally within 30 days of installation. It's fairly costly at $0.65/sq. ft., or $910 plus freight/handling, for a roll measuring 14 ft by 100 ft. It's intended to control rooted plants in smaller areas and has a useful product life projected at 5-10 years. Installation can be performed by the homeowner. We sell a considerable amount of this product to residents on ponds and lakes where no organized weed control program exists.
1999 Lake Resident Survey Results
Objective: The main objective was to make sure that the Board's efforts are focused in areas that residents feel are high priorities. A secondary objective was to learn a little more about why people chose to live here, for how long, what they've done for the lake, etc.
A total of 140 surveys were distributed, 72 were returned (51%).
1. How long has your Family been living on Bungay lake? · 27% = Less than 5 years · 15% = 5 to 10 years · 31% = 10 to 25 years · 17% = 25 to 50 years · 11% = Over 50 years
. What one attribute best describes your choice to live on the water. In other words, which do you value most? · 39% = Recreational use (swimming, boating, fishing, etc.) · 47% = Solitude, quite atmosphere (wildlife, ever-changing views, etc.) · 14% = The lake lifestyle (entertaining, community, boat parade, etc.) Other reasons noted: - "3 generations of ownership" - "Private lake"
3. What do you believe are the most important lake issues that the Board must address? (Shown most important to least important): · #1 (11.90%) = Weed control · #2 (11.76%) = Water quality improvements · #3 (11.63%) = Lake water level (Witch Pond well sites) · #4 (7.94%) = Recreational safety. · #5 (7.87%) = Dredging · #6 (7.35%) = Watershed management · #7 (5.85%) = Property damage and thefts · #8 (5.4%) = Noise control
Other important issues noted: Clean Bungay river, septic education, geese control, Homestead Restaurant concerns, PWC (Jet-Ski) education, Right-of-ways, property maintenance, and Lake clean-up efforts.
4. Once the highest priority issue is identified above, would you be willing to endorse a special financial "assessment" to support its resolution? · 83% = Yes · 17% = No A general comment was "with-in reason".
5. If the Board of Directors could do just one thing for the lake this year, what would it be? The top 5 themes are outlined below. · #1 (37%) = Increase dredging & weed control efforts · #2 (17%) = Understand/Propose water level control standards · #3 (11%) = Improve water quality activities, document, publicize · #4 (7%) = Implement recreational safety program lake-wide · #5 (6%) = PWC education and noise control
6. What have you done recently to help manage, protect and preserve your lake resources? The top 4 themes are outlined below. · #1 (36%) = Regularly remove weeds and debris from shore-line · #2 (19%) = Use low pH fertilizer on lawn (or none at all) · #3 (15%) = Replaced Septic recently / Septic pumped regularly · #4 (12%) = Use non-pH household products and chemicals
Other important efforts noted: established lake-front buffer zone, built retaining walls, did NOT add sand to beach area, participated in past Associations/efforts, and "paid my dues".
1997 Lake Conference
"Our New England Waters"
The Fourth New England Lake Conference, hosted by URI Cooperative Extension Water Quality Program, took place on June 8th, 1997 and was supported by many Federal and State conservation agencies. The theme this year was "Sharing Successes/Building the Future" Of special note to us was the participation of Mass Congress of Lakes and Ponds, Mass DEM, and Mass Riverways Program.
Attending as many concurrent sessions as possible, we learned many interesting facts about lake management. This short outline will acquaint you with some of these topics and, hopefully, motivate you to become more involved with the preservation and improvement of our lake.
The URI Watershed Watch started 10 years age with 25 volunteers monitoring 15 locations. They now have 250 volunteers monitoring 110 locations. They are an outstanding example of volunteer commitment. Not only have they learned to operate equipment and take samples, but have actually received state and federal certification. An extensive comparison test of their procedures proved their results were slightly better than professional organizations.
Volunteers can make a difference! Pinewood Lake in Connecticut is not unlike Bungay Lake in many of the problems it faces with water quality and environmental decline. A dedicated group of volunteers launched a program to determine baseline water conditions. Because funds were limited, they borrowed equipment, pursued donations, and even designed some very innovative devices for strator sampling. They learned to operate and calibrate the equipment and developed written procedures for sampling and record keeping.
A joint federal-state-volunteer program is underway to collect water quality data from lakes across Massachusetts to develop a satellite-based capability for lake monitoring. The data collected will be incorporated into a database used to correlate lake conditions with Landstat Thermatic Mapper satellite imagery.
A study was done of Community Services costs in Massachusetts, Rhode Island, and Connecticut. It was determined that for every $1.00 raised from residential development, an average of $1.14 was spent on services. On the other hand, for every dollar spent on open space, forest or farm, only 42 cents was spent on services. The study clearly demonstrates that protection of open space plays an important role in a community's long term fiscal well being.
A researcher at the University of Connecticut is developing a computer model to try to quantify the changes in property values as water quality declines. Most current data available is only in the extremes: pristine water or badly polluted. The study hopes to determine "in between" points and their affect on values
Rhode Island seems to be the leader in New England for the conservation and evaluation of innovative waste water treatment systems. URI has even set up an on-site Wastewater Treatment Demonstration Center. They outlined some of the very challenging sites that required new alternative and innovative designs. Some were very high-tech, expensive systems. Others used older technology but in innovative and less expensive ways. If local authorities are cooperative, probably any site can have a non-polluting system installed.
Special Thanks to Robert Freerksen & Don Zecher for their participation at the Conference.
Lake Drawdown Defined
Many questions were raised recently about lowering the Lake in the winter. The following information was taken from an Environmental Fact sheet published by the NH Department of Environmental Services. Remember that "lake management is lake specific" and what is right for one lake could be harmful to another. The key is to understand the biological identity of your lake or pond before developing a management program.
What is drawdown?
Lake level drawdown and the subsequent exposure of sediments to prolonged freezing and drying is an inexpensive means of aquatic weed control. By exposing the sediments to prolonged freezing and drying (35 to 50 % of the bottom area should be exposed), some rooted plant species are permanently damaged and the entire plant, including roots and perhaps seeds, are killed if exposed to freezing for several weeks.
The effectiveness of a winter drawdown is dependent upon a deep frost and complete dewatering of the sediments. These conditions may not occur with heavy snow cover or milder, rainy winters. The technique is species-specific. Some species of aquatic weeds will not be affected and some species will increase in abundance. Freezing and desiccation are required; wet, cold lake sediments, or wet sediments covered with snow may have little negative effect on plants. Drawdown should be alternated every two years with no drawdown, so that resistant species do not become firmly established.
Advantages of Drawdown
-Inexpensive means of aquatic weed control. -Absence of machinery or toxic chemicals. -Improvements to docks, dams and swimming areas can be made.
Disadvantages of Drawdown
-Possible algae blooms after reflooding, due to nutrient release from sediments. -Reduction in diversity and abundance of benthic invertebrates that are essential to fish and waterfowl diets. -Consolidation of fish population into a more centralized area of deep water, making them more susceptible to overharvesting. -Oxygen in remaining pool can be depleted leading to a fish kill. -Amphibians and other fauna of the littoral zone may exhibit great changes in species composition and density. -Early Spring herbicides may need to be applied if weeds persist and begin to sprout.
Water level drawdown is an effective technique for at least the short-term control (1-2 years) of susceptible aquatic weeds, and can be accomplished at low cost without the introduction of chemicals or machinery. However, this technique is species specific and requires careful identification of the target plants before drawdown to avoid rapid establishment of resistant species.
Bungay Drawdown Comments
During our lake level discussion at the 1998 annual meeting, we had a questions come up about lake drawdown. What effect would lake drawdown have on the non-native species, the desirable native plants, fish and wildlife, etc.?
I posted this questions and our situation up on the internet into some lake and pond management discussion groups. I received some excellent feedback from many professionals in the field including:
- Scott Seymour, Aquatic Systems Inc., Butler WI, (30 years of Environmental pond and lake management).
- Dr. Mark D. Mattson, Water resources Research Center, University of Massachusetts.
- Steve DeKozlowski, South Carolina Department of Natural Resources.
- Richard S. McVoy, Ph. D., DEP, Office of Watershed Management, Worcester, MA
- Robert Hartzel, Mass DEM, Office of Water Resources, Boston, Ma, Lakes and Ponds Program.
Below is a summary of all their comments:
To have any effect on the nuisance non-native species (Cobomba and WaterMilfoil), you would have to drawdown the lake low enough for the roots to freeze. Because these roots reside in the sediment or "muck", this would mean a drawdown of 6 to 8 feet. In a lake that's only 12 to 15 feet deep, this would have adverse effects in many other areas.
The native plant Vallisneria (eel grass), which is very desirable, grows in the shallows and could potentially get wiped out in the process. This plant (which is seed germinating) actually acts as a barrier and helps keep out many non-native species (which reproduce by fragmentation). This much drawdown would also deplete the dissolved oxygen supply resulting in a potential winter fish kill. It would not have any impact on the algae condition since this is a nutrient overload issue.
Many studies show that even after such a drawdown, there's no guarantee that the non-native plants won't come back the following year. Your best bet is to keep the lake at it highest maintainable level year round and look into other forms of nuisance plant management control.
On May 2nd, 1996, a letter was received from The Commonwealth of Massachusetts Executive Office of Environmental Affairs (Department of Environmental Protection, One Winter Street, Boston, Ma 02108, 617- 292-5500) addressed to the North Attleboro Board of Selectmen. They were asked whether or not Bungay Lake was considered a "great pond" and therefore had to comply to Chapter 91 Regulations (the registering of all docks, retaining walls, etc.)
The following was their response:
The Department of Environmental Protection, Waterways Regulation Program is responsible for administering and enforcing M.G.L. Chapter 91. Recently, the Program completed an initial review of maps and documents relating to Great Ponds of the Commonwealth. A Great Pond is a lake or pond which was ten acres or more in it's natural state.
As a result of our preliminary findings, we have determined that there are no Great Ponds within your municipality. However, should anyone have evidence that a Great Pond does lie within the boundaries of your municipality, we will revise the draft list to include that pond.
Jill E. Provencal, Cartographer, Waterways Regulation Program"
Thanks to all who got involved!
P.S. These findings have nothing to do with Boat Registration! Regulations by the Commonwealth of Massachusetts require registration for all vessels equipped with propulsion. This is enforced by the Massachusetts Environmental Police (as you may have seen!). The Board strongly recommends complying to these regulations. Please call us with any questions.
What Is Meant By Dredging?
Dredging is basically the removal of sediment and other material from a lake or pond and there are two basic types. "Dry dredging" is a process of draining the lake completely and using heavy machinery to remove the sediment and gravel. "Wet dredging" removes the material while it's still under water, using a barge and vacuum pumping system, allowing the lake to still be partially used. Either way you get there, dredging has its benefits and detriments.
- Increasing the depth of shallow lakes has long-term advantages. Adequate depth promotes fish growth, discourages weed growth, lowers water temperatures, increased oxygen levels, and recreational boating opportunities.
- Dredging can effectively remove plants, organic matter and nutrients. The removal of nutrients and sediment will reduce the internal nutrient loading, and help to discourage further growth of some types of algae and weeds.
- dredging can be site specific and directed at target areas.
- depending on the method used, you may temporarily displace or kill some of the living organisms including fish and bethnics.
- portions of the use of the lake for human activities are precluded during dredging.
- disposal of the dredged spoils is costly and may pose environmental impacts.
- dredging should not be viewed as a viable method for managing aquatic weed and algae growth. Only about 10% of the ponds that have been dredged in New England for the purpose of managing plant growth have effective management for more than two years. Most lakes experience a regrowth of aquatic vegetation quite readily after dredging.
- because dredging does nothing for the nutrient overload being imposed on the lake by its residents, high concentrations of algae is a post-dredging problem.
As with any lake management technique or project, there are advantages and disadvantages to consider.
Effective lake managers must focus on the results and not the activities.
What is Eutrophication?
The term eutrophication is now generally used, even by most scientists, to describe both nutrient levels (the amount of foodstuff available for plant growth) and the natural "aging" of a lake. Eutrophication is the process of increased nutrient input to a lake over the natural supply. From the instant that a lake is created, the aging process, or filling-in, begins. Material is carried from the watershed by streams, wind and direct runoff to become deposited in the lake. They also age at different rates because of differences in geology, runoff and watershed characteristics.
Bungay is considered a eutrophic lake, one which is shallow with a soft mucky bottom. Rooted plant growth is abundant along the shores and out into the lake, while algae blooms are not unusual. The water is often colored, with suspended and organic matter reducing its clarity. Eutrophic lakes support only warm water fisheries such as perch, horned pout and bass.
Any activity in which man increases the rate of incoming materials (such as land clearing, and watershed development) or increases the nutrient loading (septic leaching, fertilizers, etc.) will hasten this aging process. This is often called cultural eutrophication.
Why has Bungay filled in or "aged" so much over the past 40 years?
As we learned above, all lakes gradually fill in over time. If a lake is experiencing a nutrient overload, it will fill in much faster that one that isn't. At one time, Bungay Lake used to be 90% summer cottages. Over the past 30/40 years, we've reversed that to 90% full time residences. This results in nutrient overload that is nearly 6 to 10 times the previous amount. The chart below shows typical phosphorus levels for cottage living compared to year round living.
-Human Waste = 534 grams, -No Dishwasher = 0 grams, -Doesn't Fertilize = 0 grams, -Wooded Lot = 17 grams, -Phosphate Free Household Products = 0 grams, -Total = 551 grams
Year Round Residence
Human Waste = 1534 grams, -Dishwasher, Powdered Detergent = 651 grams, -Fertilizes Lawn Twice per Year = 1962 grams, -Clears Lot = 29 grams, -Household Products Containing Phosphates = 180 grams, -Total = 4356 grams
Bungay Lake is the way it is today mostly because of the way we have been treating it over the past several years. See articles on nutrient reduction in this archive to discover what YOU can do to help prevent nutrient overloading.
Groundwater & Surface Water
Groundwater & Surface Water: Understanding the Interaction
Test your groundwater IQ.
1. Which ways can groundwater move?
a. Up / b. Down / c. Sideways / d. All of the above
2. How is the speed of groundwater movement measured?
a. Feet per day / b. Feet per week / c. Feet per month / d. Feet per year
3. How is stream flow usually measured?
a. Feet per second / b. Feet per minute / c. Feet per hour / d. Yards per hour
4. What determines how fast groundwater moves?
a. Temperature / b. Air pressure / c. Depth of water table / d. Size of materials
5. Can the water table elevation change often?
a. Yes / b. No
Does aquifer storage capacity vary?
a. Yes / b. No
1. d. All of the above Although most movement is lateral (sideways), it can move straight up or down. Groundwater simply follows the path of least resistance by moving from higher pressure zones to lower pressure zones.
2. d. Feet per year Groundwater movement is usually measured in feet per year. This is why a pollutant that enters groundwater requires many years before it purifies itself or is carried to a monitored well.
3. a. Feet per second Water flow in streams/rivers is measured in feet per second.
4. d. Size of materials Coarse materials like sand and gravel allow water to move rapidly. (They also form excellent aquifers because of their holding capacity.) In contrast, fine-grained materials, like clay or shale, are very difficult for water to move through. Thus, water moves very, very slowly in these materials.
5. a. Yes Water table elevations often fluctuate because of recharge and discharge variations. They generally peak in the winter and spring due to recharge from rains and snow melt. Throughout the summer the water table commonly declines due to evaporation, uptake by plants (transpiration), increased public use, industrial use, and crop, golf course and lawn irrigation. Elevations commonly reach their lowest point in early fall.
6. a. Yes Just like the water level in rivers and streams, the amount of water in the groundwater supply can vary due to seasonal, weather, use and other factors.
Groundwater: A Hidden Resource
Groundwater is a hidden resource. At one time, its purity and availability were taken for granted. Now contamination and availability are serious issues. Some interesting facts to consider... Scientists estimate groundwater accounts for more than 95% of all fresh water availablefor use.Approximately 50% of Americans obtain all or part of their drinking water fromgroundwater.
Nearly 95% of rural residents rely on groundwater for their drinking supply. About half of irrigated cropland uses groundwater. Approximately one third of industrial water needs are fulfilled by using groundwater. About 40% of river flow nationwide (on average) depends on groundwater. Thus, groundwater is a critical component of management plans developed by an increasing number of watershed partnerships.
Groundwater is the water that saturates the tiny spaces between alluvial material (sand, gravel, silt, clay) or the crevices or fractures in rocks.
Aeration zone: The zone above the water table is known as the zone of aeration (unsaturated or vadose zone). Water in the soil (in the ground but above the water table) is referred to as soil moisture. Spaces between soil, gravel and rock are filled with water (suspended) and air.
Capillary water: Just above the water table, in the aeration zone, is capillary water that moves upward from the water table by capillary action. This water can move slowly in any direction, from a wet particle to a dry one. While most plants rely on moisture from precipitation that is present in the unsaturated zone, their roots may also tap into capillary water or into the underlying saturated zone. Aquifer: Most groundwater is found in aquifers-underground layers of porous rock that are saturated from above or from structures sloping toward it.
Aquifer capacity is determined by the porosity of the subsurface material and its area. Under most of the United States, there are two major types of aquifers: confined and unconfined. Confined aquifers (also known as artesian or pressure aquifers) exist where the groundwater system is between layers of clay, dense rock or other materials with very low permeability.
Water in confined aquifers may be very old, arriving millions of years ago. It's also under more pressure than unconfined aquifers. Thus, when tapped by a well, water is forced up, sometimes above the soil surface. This is how a flowing artesian well is formed. Unconfined aquifers are more common and do not have a low-permeability deposit above it. Water in unconfined aquifers may have arrived recently by percolating through the land surface. This is why water in unconfined aquifers is often considered very young, in geologic time. In fact, the top layer of an unconfined aquifer is the water table. It's affected by atmospheric pressure and changing hydrologic conditions. Discharge and recharge rates depend on the hydrologic conditions above them.
Saturation zone: The portion that's saturated with water is called the zone of saturation. The upper surface of this zone, open to atmospheric pressure, is known as the water table (phreatic surface). How Groundwater and Surface Water connect. It's crystal clear. Groundwater and surface water are fundamentally interconnected. In fact, it is often difficult to separate the two because they "feed" each other. This is why one can contaminate the other.
A closer look.
To better understand the connection, take a closer look at the various zones and actions. A way to study this is by understanding how water recycles ... the hydrologic (water) cycle. As rain or snow falls to the earth's surface: Some water runs off the land to rivers, lakes, streams and oceans (surface water). Water also can move into those bodies by percolation below ground.
Water entering the soil can infiltrate deeper to reach groundwater which can discharge to surface water or return to the surface through wells, springs and marshes. Here it becomes surface water again. And, upon evaporation, it completes the cycle. This movement of water between the earth and the atmosphere through evaporation, precipitation, infiltration and runoff is continuous.
How groundwater "feeds" surface water.
One of the most commonly used forms of groundwater comes from unconfined shallow water table aquifers. These aquifers are major sources of drinking and irrigation water. They also interact closely with streams, sometimes flowing (discharging) water into a stream or lake and sometimes receiving water from the stream or lake. An unconfined aquifer that feeds streams is said to provide the stream's baseflow. (This is called a gaining stream.) In fact, groundwater can be responsible for maintaining the hydrologic balance of surface streams, springs, lakes, wetlands and marshes.
This is why successful watershed partnerships with a special interest in a particular stream, lake or other surface waterbody always have a special interest in the unconfined aquifer, adjacent to the water body.
How surface water "feeds" groundwater.
The source of groundwater (recharge) is through precipitation or surface water that percolates downward. Approximately 5-50% (depending on climate, land use, soil type, geology and many other factors) of annual precipitation results in groundwater recharge. In some areas, streams literally recharge the aquifer through stream bed infiltration, called losing streams.
Left untouched, groundwater naturally arrives at a balance, discharging and recharging depending on hydrologic conditions. Common boundaries.
Aquifers are often difficult to delineate. It requires someone with an understanding of the aquifer, the geology, the surface above it, and the land that drains toward the surface. An unconfined aquifer area often extends to the surface waterbody's (i.e. lake, river, estuary) watershed. When determining an aquifer protection area, pumping (working) wells are not considered. The biggest risk to an unconfined aquifer is contaminated water moving through the permeable materials directly above it. This area is known as the primary recharge area. Depending on the depth and overlying geologic characteristics, travel time from the surface to the aquifer can be relatively short.
When pumping wells are located near a stream or lake, infiltration can be increased. Infiltrating streams typically provide an aquifer with large quantities of water and a pathway for bacteria, viruses and other contaminants.
A confined aquifer area may be limited to the outcrop of the aquifer unit and its immediate contributing area. This area may actually be isolated from the location of water supply wells within the aquifer. Semi-confined aquifers may receive water from both outcrop areas and overlying aquifers. Delineating the aquifer protection area can be extensive and complex. Sole-source aquifers are delineated based on aquifer type - confined, semi - confined or unconfined - and local geologic and hydrologic conditions. Defined as providing a minimum of 50% of the water for its users, sole-source aquifers usually exist only where there simply are no viable alternative water sources.
Wellhead protection areas (also known as zone of contribution and contributing areas) are the surface and subsurface areas surrounding a well or field of wells (wellfield) supplying a public water system.
Threats to quantity.
When an increased quantity of groundwater is being withdrawn to meet the demands of a growing population, typical threats such as overdraft, drawdown and subsidence can occur. Overdraft occurs when groundwater is removed faster than recharge can replace it. This can result in a permanent loss of a portion of its storage capacity. A change that can cause water of unusable quality to contaminate good water. Generally, any withdrawal in excess of safe yield (the amount that can be withdrawn without producing an undesirable result) is an overdraft.
Drawdown differs significantly from overdraft. It results in a temporarily lowered water table generally caused by pumping. In this situation, the water table recovers when the supply is replenished. Subsidence is one of the dramatic results from overpumping. As the water table declines, water pressure is reduced. This causes the fine particles that held water to become compacted. In addition to permanently reducing storage capacity, the land above the aquifer can sink ... from a few inches to several feet ... causing a sinkhole. This can damage property and fields.
Lake Restoration Versus Lake Management?
A complex and potentially controversial topic that can mean various things to different lake user groups. Lake restoration often connotates attempting to return a lake to an original or previous condition - usually with a desire for clearer water (less algae) and fewer vascular plants, by the recreational user.
Management, on the other hand, typically refers to action(s) taken to produce a desired condition. Once the ecological balance has been altered, either through human intervention or acts of nature, the lake system can never truly be "restored" but only "managed." Prudent "management" of our valuable pond/lake resources is a shared responsibility between the lake user/owner, professional lake managers and the regulatory community.
Dredging Not Always a Solution to Lake Problems
Dredging is often an appropriate lake management technique to provide added water depth and volume and potentially remove nutrient reserves that continue to support nuisance vascular plants and algae. In some situations, dredging will also reduce the abundance of rooted aquatic plants, primarily through limitation of light penetration and to a lesser extent by changes in bottom substrate.
During the 1970's and 80's USEPA and state agencies funded a number of New England dredging projects, each to the tune of several hundred thousand dollars or more. Specific dredging projects that come to mind include: Nuttings Lake (Billerica, MA), Morses Pond (Wellesley, MA) and 1860 Reservoir (Wethersfield, CT). A primary goal in dredging all of these waterbodies was to provide long-term control of nuisance rooted vegetation and/or algae. Within roughly 1-2 years from completion of dredging, however, these same lake communities experienced severe nuisance weed/algae conditions.
At Morses Pond, there is a reason to believe the pond dredging actually spread the plant (milfoil) infestation. What went wrong with these projects? To some extent, the potential benefits of dredging were "oversold" by the project proponents particularly in light of the limits imposed by funding and disposal options. Seldom will dredging alone, control invasive plants like milfoil through changes in bottom substrate.
People, Lakes and Land
People, Lakes, and Land: Puzzling Relationships
In the early years of what is now called "lake management", scientists and citizens alike focused on restoring the quality of degraded lakes through a myriad of in-lake techniques and activities in the near-shore area. Simple predictive models were used and goal-setting tended to be neglected. If goals were mentioned, they often were wishful comparisons with pristine environments elsewhere. Often, similar management techniques were used from lake to lake forgetting that "lake management is lake specific".
As the science of lake management evolved it became obvious that focusing exclusively on a lake was not enough -- we had to consider the watershed as well. This expansion of focus created not only new partners in lake management but new challenges as well. It improved our predictive tools, enhanced our understanding of the relationships between lakes and watersheds, and created opportunities to involve more people in lake management.
The evolution of lake management continues. Today, we are building broader relationships that look at regional and national lake and landscape patterns. This has improved our understanding of the potential relationships between lakes and the broader patterns of our landscape. This new vision has improved our ability to set resource goals and increase the emphasis on protecting lakes rather than expensive restoration efforts.
However, at each step in the evolution of lake management, it has become increasingly important to take into account the people who are involved, be they lakeshore residents, local planning and zoning authorities, university staff, consultants, or government resource managers. Developing good working relationships between these and all other groups involved ultimately will do the most to protect our lake resources.
Thus, the people side of lake management has become increasingly important. It means we have had to improve our skills for dealing with each other as individuals or organizations, and for managing and nurturing volunteers, educating people on lake and land stewardship, and working to change attitudes on how lakes should be used or shoreline areas managed.
It seems safe to say the continuing development of relationships between people, lakes, and land will create new and challenging problems for lake management. But, by building partnerships, and remembering that "lake management is lake specific", these challenges will be puzzling but not impossible.
Reflecting on Lakes
How protecting your watershed can improve your lake
A high quality lake, valued for recreation and aesthetic appeal, can benefit all watershed residents (and nonresidents alike) by providing a healthy place to play and/or enjoy a quiet sunset. In other words, a high quality lake improves the quality of the community's life. Property values, not only on the lakeshore, but throughout the watershed community, can benefit from a desirable lake.
Six keys to protecting lakes
1. Valuing high quality lakes
2. Understanding the link between the lake and its watershed
3. Understanding in-lake processes
4. Recognizing and preventing threats to lake quality
5. Forming partnerships with lake-watershed members
6. Knowing where to go for help
A lake is the reflection of its watershed (the land that drains -- eventually -- into it) and the everyday actions that take place on the watershed. The importance of the relationship between a lake and its watershed cannot be over emphasized when protecting, managing or restoring a lake. The lake-watershed "system" is a functioning unit with interacting biological, physical, chemical and human components.
If a lake suffers from problems such as extensive weed growth or algal scum, fish kills, or filling in with sediments, often the cause of the problem can be linked to a source or sources within the watershed.
The characteristics of lake-watershed interaction depend on a number of variables. Some variables include the ratio of drainage area to lake area, how the land is used, the climate, soils and geography, as well as existing conservation measures.
Sizes and shapes
The origin of a lake often determines the size and other characteristics of the lake. "Man-made" lakes, often referred to as impoundments or reservoirs, are those that were formed by damming a drainageway, stream or river. Man-made lakes can range in size and shape from the smallest farm pond to huge "run-of the-river" reservoirs such as Lake Mead formed by the Hoover Dam.
Lake-watershed size relationship
If a lake is small relative to its watershed, the potential is greater for the lake to fill in with sediment or be affected by nutrients tied to the soil particles, than a large lake with a relatively small watershed.
Climate and soils
Lakes in areas with more rainfall and steep, erosive, nutrient-rich soils will have greater potential for algae blooms and plant growth than those in dry climates with infertile soils.
In general, the greater the slope of the land in the lake's watershed, the greater the potential of pollutants reaching the lake.
Lake productivity stages
In-lake factors combined with the lake-watershed relationship, determine how "productive" a lake will be. The biological productivity of a lake is based on the availability of plant nutrients and is referred to as the lakes "trophic" condition. Extremely high or low productivity usually limits aquatic life. High productivity leads to lots of algae and other aquatic plants. Low productivity leads to very little aquatic life.
The trophic condition of lakes ranges from the least productive (oligotrophic) to moderately productive (mesotrophic) to highly productive (eutrophic). Hypereutrophic lakes are the most productive of all. The process of moving from an oligotrophic state to a eutrophic state, is a natural process that can take thousands of years, as sediment from the watershed carries nutrients slowly into the lake.
However, where human activity has affected a watershed, lake productivity can dramatically increase over a relatively shorter period of time. This type of eutrophication--as a result of watershed disturbance by humans -- is known as "cultural" eutrophication.
TMDL Definition -- What is a total maximum daily load (TMDL)?
A TMDL or Total Maximum Daily Load is a calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant's sources.
Water quality standards are set by States, Territories, and Tribes. They identify the uses for each waterbody, for example, drinking water supply, contact recreation (swimming), and aquatic life support (fishing), and the scientific criteria to support that use.
A TMDL is the sum of the allowable loads of a single pollutant from all contributing point and nonpoint sources. The calculation must include a margin of safety to ensure that the waterbody can be used for the purposes the State has designated. The calculation must also account for seasonable variation in water quality.
The Clean Water Act, section 303, establishes the water quality standards and TMDL programs
What is a Secchi Disk?
A Secchi disk is an 8-inch Diameter disk with alternating black and white quadrants. It is lowered into the water of a lake until it can be no longer seen by the observer. This depth of disappearance, called the Secchi depth, is a measure of the transparency of the water.
Transparency can be affected by the color of the water, algae, and suspended sediments. Transparency decreases as color, suspended sediments, or algal abundance increases.
Water is often stained yellow or brown by decaying plant matter. In bogs and some lakes the brown stain can make the water the color of strong tea. Algae are small, green aquatic plants whose abundance is related to the amount of plant nutrients, especially phosphorus and nitrogen.
Transparency can therefore be affected by the amount of plant nutrients coming into the lake from sources such as rain runoff, septic tanks, and lawn and agricultural fertilizer. Suspended sediments often come from sources such as resuspension from the lake bottom, construction sites, agricultural fields, and urban storm runoff.
Transparency is an indicator of the impact of human activity on the land surrounding the lake. If transparency is measured through the season and from year to year, trends in transparency may be observed. Transparency can serve as an early-warning that activities on the land are having an effect on its quality.