2008 WLA Water Quality Monitoring Final Report Commentary

Introduction

This document references information contained in the formal slide presentation of the 2008 Final Webster Lake Water Quality Monitoring Report and must be used in conjunction with the information displayed in the slides and the supporting database.

Per the QAPP, the 2008 plan continued the monitoring activities at the 3 deepest pond locations in 2 ft depth increments along with monitoring five feeder stream locations. In addition to these continued activities, the 2008 plan added the testing of 12 cove locations around the lake using a nitrate sensor on the Troll 9500. This latter activity was done on a trial basis to locate potential hot spots in the lake shoreline areas.

While the size of the presentation in terms of time to present did not allow comparisons to prior years, the 2008 data was reviewed against the historic average for the prior 3 years and the most significant deviation from the historic average is discussed in this document. While 3 prior years is significant, it is too short a period to be able to identify any trends in the data.


Discussion of findings for the 2008 monitoring season

Temperature
Water temperatures in both the lakes and stream followed historic averages. It is believed that any differences can be explained by weather patterns. The unusually high rainfall amounts in July coupled with a warm July and August continued to show it impact on water temperatures well into September resulting in the water temperatures at depth in September running above the historic averages. Historically the thermo cline in September was at approximately 26 ft in depth. This September, that depth was approximately 32 ft.

Dissolved Oxygen
DO levels reached their lowest levels in July and August where DO began dropping of sharply from their upper layer levels of approximately 8mg/l at 14 ft and dropping below 2mg/l beyond 24 ft and showing near 0mg/l beyond 30 ft. The stress levels on the lake were demonstrated by how shallow the depth at which DO levels sharply dropped off. This suggests that the combination of temperature and nutrient loading are overpowering the lake in the warmest months.

The streams showed good levels of DO throughout the season remaining mostly above 8mg/L with the exception of July where Sucker and Browns brooks dropped down close to 5mg/L.

Oxygen Reduction Potential (ORP)
ORP is turning out to be one of the top indicators of water quality. ORP indicated the ability of the water to oxidize or consume pollutants including bacteria, algae, and other nutrients in the water. The ORP readings for the lake indicated that the warm season took its toll on water quality. ORP showed “Out of balance” for August and October at all depth levels with values in August dropping into the “Harmful to fish” levels.

OPR values for the streams remained in the “in balance” or “has reserve capacity” with the exception of Sucker Brook which tested “out of balance” in June.

pH
All lake readings for the season remained in the good range through the season

The streams tested in the “good” range except for October where Sucker, Mine, and Brooks all tested in the “elevated salts” range.

Salinity (Conductivity)
All lake tests indicated conductivity levels below 200 uS/cm for the all tests throughout the season. July showed the highest readings most likely caused by the nearly 6 inches of rain across a 4 day period in the month. This caused high flow levels in the streams for a short period of time likely carrying with it a higher concentration of salt from the stream banks and feeder tributaries.

Most stream values tested at less than 100 uS/cm for all months except July where Sucker, LKQ Outflow, and Un-Named Brook indicated values in the 220 to 260 uS/cm range.

Clarity (Turbidity)
The reading this season provide a surprise behavior in the lake. Turbidity remained below 105 NTU for all months with the exception of August. (Spikes in Sept and Oct are to be ignored because they are the result of averaging S1, M1, and N1 water columns, readings into a single average and those spikes are due to S1, and M1 bottom readings) However, August shows that Turbidity above the thermo cline was normal while readings below the thermo cline showed elevated turbidity levels. In studying the possible reason for this, my conclusion is that it is probable related to the heavy rain influx in July. ORP levels in August suggest that ORP above the thermo cline remained high enough to keep the algae bloom from forming but below the thermo cline where it drops sharply, the algae was able to overpower the oxygen and was able to form a bloom. The gradual improvement of Turbidity values as depth increased suggest that even the algae bloom was constrained from lack of light and oxygen.

Turbidity readings in the streams showed that Turbidity reading followed runoff volumes increasing slightly in the months where higher runoff levels were present. The one exception is the LQK outflow where readings for most of the season were very high. While the volume of water from the LKQ runoff source is very low, the readings indicate that there is a runoff issue from this source.

Chlorophyll-A
This parameter is only tested in the lake water. All tests for the 2008 season showed all readings to be below 3.5 mg/m3 well within the “good” 0-5mg/m3 range.

Phosphorus
Total P for all lake samples tested in the “good” range and all results were between .01-.022 mg/L.

Total P for streams showed Phosphorus loading which varied across the season. The readings showed the following results:
Scale (mg/L) April May June July Aug Sep
Un-Named Fair VG VG Fair Fair Fair
Browns Good Fair Fair Fair Fair Fair
Mine Fair VG VG Fair Fair Fair
Sucker Fair VG VG Fair Fair VG
Fair(.03-.06 mg/L) Good(.01-.03mg/L) Very Good(VG)(<.01mg/L)
These results suggest that Phosphorus loading in the lake is being contributed to by the feeder streams. Browns Brook shows a different performance line across the season than the other streams which suggests there are unique influences at play that affect the readings from Browns

Nitrates
A nitrate sensor was added to the Troll 9500 for the 2008 season. The sensor’s accuracy is rated at +/-10%. Calibration of this sensor has to be done immediately before testing is done. The purpose of adding the sensor was to perform “go/no go” testing of selected shoreline areas to look for potential problem spots. Since Nitrates samples for the 3 deep spot locations were also performed by external lab testing and with our own Colorimeters, there were solid references to compare the results against. Readings from the Troll taken at the 3 deep spots were compared with the lab results and indicated the Troll sensor was operating within it accuracy specifications.

The lake deep spot readings yielded surprising results. Readings for the cold water months of May and June indicated Nitrate levels that were pretty much in the “background” range. As the water warmed throughout the season, values increased as would be expected. However, as water warmed all the way to the bottom and eliminated the thermo cline, the readings for Nitrate values spiked up from <1.0ppm to nearly 2.5ppm.

Testing in the cove areas did not reveal any significant issues. The power point presentation includes a map with the 12 cove locations marked. These locations were selected by the water quality monitoring team with addition inputs from lake association members. The selected locations included the following location: IDs letters S, M, N indicate South Pond, Middle Pond, and North Ponds
ID Location Rational For Testing
S2 Below State Boat Ramp Heavily weeded
S3 At Wakefield Ave Ent Left Cove Heavily weeded
S4 At Wakefield Ave Ent Right Cove Weeds/Runoff Source
S5 Far southwest part of pond Heavily weeded
S6 Cove to the east of ent. to mid pond Heavily weeded
M2 Far end of sailing club cove Heavily weeded
M3 East shore in smith cove near Indian Ranch Browns Brook Outflow
M4 Cove- west side just south of ent. to N pond Weeds/runoff
M5 West shore in corner by I-395 Runoff from I-395
M6 Cove inside Action Marine-near west shore Runoff
M7 Outflow pipe in wall above Act Marine Ent Runoff
N2 Channel below Rt 16 bridge Sucker/ Mine Outflow
The results show slightly elevated readings over those taken at the deep spot locations. South pond showed slightly elevated levels over Middle and North ponds. This seems to be consistent with lower ORP levels in South pond possibly as a result of not having any constant feeder streams into South Pond. North Pond which has two feeder streams had the best readings. Again the differences were small but consistent across the testing period.

One other notable worthy observation is that the two coves located near the corner of Wakefield and Lakeside Ave showed the highest readings across the seasons. This is the location that is currently on the list of shovel ready projects for possible stimulus money which would implement a sediment removal solution for the runoff that travels through several neighborhoods and along Lakeside Ave before entering the lake in the cove labeled with the ID S4 in this report. This runoff source is aggressive in wet weather but stops running in dry weather.

The streams contributed to Nitrate loading in the lake with the Sucker and Mine yielding readings of 2.5-3.5ppm for the months of July and August. This is to be contrasted to the other streams which tested below 1.0ppm for the season.

Major Current Actions
• Weed Treatments (chemical controls currently being used)
• Arrest sediment in runoff using catch basins, holding ponds, grass swales, etc(being done as funding allows)
• Septic system disconnects
• Awareness and education programs

Additional Things That Would Help
• Removal of weeds/leaves deposited on the shoreline
• Manage disturbances in the watershed differently than other areas (erosion, construction, paving runoffs, brush/leaves, sewers, logging, road sand and salts, fertilizers, etc)
• Weed Harvesting or chemical treatment of native weeds. When the invasive weeds are eliminated, the native weeds feed on the excessive sediments in the lake and take over causing the same negative impact on water quality that invasive weeds were causing.
• Any inactive watershed construction should be required to seed the site with grass to prevent erosion and reduce runoff
• Require that finished watershed lots be seeded as part of the build phase and not left unplanted.
• Do not allow tree removal or top soil to be stripped on watershed lots until the active construction phase of a lot proceeds.
• Do not allow any tree removal for construction, logging, etc. where the trees provide shade to the steams and their feeding tributaries. Some stream go dry for a couple months but they remain streams for the other 9-10 months out of the year and if construction or logging are approved, impact to the lake results for that action.
• Do not allow mass clearing of watershed building lots, keep as many trees as possible and allow removal of only what is needed.
• Require that site runoff conforms to good watershed practices both during construction and in the finished plan.
• Require that finished sites include catch basins, grass swales, etc. to arrest sediments before they enter feeder streams or feed directly into the lake.
• Dredging the lake in areas of major sediment buildup would be of major help. It is the only way to reverse damage already done. As long as the sediment is there, the weeds have fertilizer and will continue to overpower the lakes ability to oxidize the ongoing nutrient loading.
• Implement a drain down plan. Experts say that if done correctly, it is the most effective method to control and destroy weeds. (Ideal is said to a 6-7 ft drain down from Oct to Mid-Jan followed by a rapid refill) This causes the weeds to dry out and be killed by the deep frost in January and then the rapid refill causes the dead material to be pulled loose and floated.) Less aggressive plans have also produced positive results.

Lake & Stream Monitoring Procedures

This explains what the Water Quality Team does, how easy it is to accomplish, while requiring just a bit of time. It is important we monitor the streams because the brooks entering the lake are the most likely places to catch any problems that may occur. Please consider joining us.
If there are any questions please don't hesitate to contact either Al Huefner or Ernie Benoit.

Al Huefner
82 Lakeside Ave
Webster, Ma 01570
(H) 1-508-275-9359
(C) 1-847-971-8190
email: HuefnerAl@aol.com

Ernie Benoit
86 Point Breeze Road
Webster, MA 01570
508-943-8804 Home
774-230-3138 Cell
email: ernieb@charter.net

To help answer questions for anyone who in interested in joining, we have prepared the brief summary below of what the activities are, how long it takes, and where we meet. We do two water quality monitoring activities:

Streams and LakeStreams Monitoring

Stream Testing - We meet at 9:45 at the far end of the Lodge Restaurant parking lot on Route 16 heading east toward Douglas. The Lodge is before you get to Indian Ranch. We check our gear and then go to the location in one or two vehicles. At the testing locations, the activities are as follows:

1. Fill out the observation sheet of visual sightings. This is a check the appropriate boxes activity using a clip board

2. Fill water sample bottles for later analysis by the Colorimeter analysis team for Nitrate and Phosphorus

3. Record sensor readings using the electronic instrument call the Troll 9500 made by In-Situ Corp.

4. Record water level readings for the staff gauges located at some sites

5. Record wind speed, air temp, and direction information using handheld instrument.We do this at 4-6 Streams locations. The total time is about 1.5-2 hr to complete all sites. All locations are near roads.

In the spring, we do take boots along in case we need them.

Lake Monitoring - The lake monitoring is a different process. We test at the deepest spot in each of the 3 ponds. We go out by boat and use a GPS instrument to position over the deep spot where we then anchor the boat. We then perform the following:

1. Fill out observation sheets of visual sightings. This is a check the appropriate box activity using a clip board.

2. Fill water sample bottles for later Nitrate, Phosphorus, and Chlorophyll-a by Colorimeter/External Lab.

3. Record sensor readings using the Troll at increments of 2 ft in depth and write down temps at each depth looking for the thermo cline(the thermal layer)

4. Use the Van Dorn sampler to capture water samples just below the thermo cline and near the bottom for Phosphorus testing.

5. Using the Secchi disk and aqua scope, perform clarity depth test.

6. Record wind speed, air temp, and direction information using handheld instrument. No training is required.

You will learn by doing the tasks guided by an experienced person each step of the way. Just come to have fun. For lake testing, we use Ray and Jeannie Travis’s boat and we leave from their house located at the far end of Mark Ave (last house on the right) at 10:45 am on the test dates. Total time runs between 2-2.5 hours to complete all three locations. If the weather does not co-operate, we will reschedule the date and we try to notify people in advance to save you from a false start.

WLA WEBSITE

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