RETURN TO MAIN WATER SUPPLY PAGE

"Candlewood Lake cannot escape its destiny as a huge potable water supplier."
- The late Frederick Benedikt, long time New Fairfield citizen activist, speaking in 1986.

The black line above represents the proposed water supply pipeline from
Candlewood Lake (on the east) up gradient to Margerie Reservoir (on the west)

INTRODUCTION
The Housatonic Valley Region is host to some of the state's largest hydroelectric facilities. Three of these are formed by dams on the Housatonic River itself. The fourth, Candlewood Lake, is a separate facility but receives pumped water from, and releases flow back to, the Housatonic River in New Milford.

A "Rocky River Power Company" was organized in 1905. It received broad rights of eminent domain for power project development from the Connecticut General Assembly.

By the later twenties, the Connecticut Light and Power Company had completed acquisition of the thousands of acres of land required for this hydroelectric reservoir. Land clearing and construction of dikes and dams began in 1927. Flooding of the valley commenced in February 1929, and by September of that year Candlewood Lake was completed with its water level near the "440 elevation" taking line.

Candlewood Lake has served the dual functions of power generation and recreation since that time. A third possible use, that of public drinking water supply, has been discussed on and off over many years.

WATER BUDGET FOR LAKE
Water within Candlewood Lake is only partially derived from that pumped up from the nearby Housatonic River. An overview of the Lake's theoretical "water budget' was prepared by the CT Agricultural Experiment Station in 1971, with figures in millions of cubic feet, as follows:

WATER ENTERING LAKE:
1,400 pumped up from the Housatonic
2,050 runoff from adjacent watershed
880 direct rainfall on Lake
4,330 total

WATER COMING OUT OF LAKE:
970 leakage via bedrock fractures
2,770 used for power generation
590 evaporation from Lake
4,330 total

LAKE AS WATER SUPPLY
IN HVCEO REGIONAL PLAN
Under the authority of State Statute Chapter 127, Section 8-35a, the HVCEO prepares an advisory plan of development for the ten municipalities of the state defined Housatonic Valley Region. The latest HVCEO Plan, adopted in 1997, as well as the earlier 1981 Plan, recommended that the municipal plans of conservation and development for the five lakeside municipalities categorize Candlewood Lake as a potential public drinking water supply source.

Such a classification includes a recommendation for maintaining conservative local land use policies to help preserve the Lake’s watershed for this vital and environmentally sensitive purpose. This designation would be in addition to its ongoing roles as a recreational and power generating resource.

In making this water supply designation HVCEO was aware that the Lake receives water pumped up from the Housatonic River, which is a state designated waste water receiving stream. State policy prohibits water supplies from receiving such waters. But the City of Danbury have developed a creative policy position to address this key point.

Any future use of Lake waters for public drinking water supply would be via withdrawal at the southern end. Such use would be preceded by division of the Lake into classifications of B (northern, continued waste water receiving from the Housatonic) and AA (southern, well away from the entering wastewater and in a non-mixing zone, thus suitable for public drinking supply).

This new classification would be preceded by studies investigating factors of the Lake's water movement and feasibility of the diversion plan. Factors to be considered include the extent to which basin recharge from such major tributaries at the southern end as Ball Pond Brook would keep wastewater away from the water supply intake, and value of water supply withdrawal only in Springtime for Margerie Reservoir to avoid conflicts with recreation, and regulatory feasibility of a dual classification with the boundary bisection the water body itself to be within existing state non-mixing law.

Concerning the overall Candlewood Lake Watershed, land cover change for 1985-2002 displayed on a map of the Candlewood Watershed is also of interest.

The Candlewood Lake Authority promotes
improvements to local land use regulations that will
positively impact the Candlewood Lake Watershed

CHRONOLOGY OF SUPPLY CONCEPT
1. 1968 USE IN A SEVERE DROUGHT:
Candlewood Lake has already been established as the “source of last resort” for the City of Danbury during an extreme drought. Such an emergency occurred in 1968 when state permission was granted for use of Candlewood Lake for water supply. A temporary pipeline and pumps operated from Candlewood to Margerie via the shortest route with the easiest slope, this route to become part of the long range plan after the report of 1986 (below).

2. HVCEO 1972 WATER MANAGEMENT STUDY:
This study reviewed the barriers to use of the Lake for public water supply. It concluded that "Regardless of these problems, Candlewood Lake should be considered as a possible regional water supply source to be developed to full capacity and adequate quality because of its considerable potential."

3. DANBURY POLICY OF 1972: Mayor Gino Arconti proposes a mile and quarter long pipeline to transport five million gallons of water per day from Candlewood Lake to Margerie Reservoir. The announcement was made after meetings with CL&P, owners of the Lake. As noted below the preliminary engineering plan for this was completed in 1986.

4. 1981 REGIONAL DEVELOPMENT PLAN:
The HVCEO Regional Plan of 1981 stated that “It is possible to divert waters from the Lake to other reservoirs during the Spring before the Lake is used intensively for recreation during the Summer. The Lake might serve as a feasible alternative for several municipalities concurrently.

Additionally, the Lake may be the only feasible alternative at a given future time if other proposed sources are not developed for water supply purpose s.... In any evaluation of the Lake as a water supply, local officials will want to see that existing recreational, environmental and aesthetic resources are protected.”

In essence the HVCEO policy of 1972 favoring Lake use for water supply was reendorsed, and the Candlewood Watershed was added to the map of "potential water supply watersheds" in the Region.

5. 1985 DEP CLASSIFICATION:
While in Connecticut Class A and AA waters are not open to receipt of additional wastewater discharges, Classes B, C and D are so available. As Class B waters from the Housatonic River are pumped up into Candlewood Lake, the Lake is also classified as B in the Connecticut system, maintained by CT DEP. How, then, to prevent discharges from using the B Classification of Candlewood to treat it as a waste water receiving water body?

The CT DEP provided an answer thru a special classification set up in the mid-1980's, stating..“there is no intent to open Candlewood Lake up to consider allowing direct wastewater discharges. Therefore, it is further recommended that an asterisk be placed next to the classification symbol (B*) and that a note be made on the map that direct wastewater discharges will not be permitted.”

6. 1986 DANBURY WATER SUPPLY DIVERSION REPORT:
According to the City of Danbury’s 1986 engineering report entitled “Investigation and Report on Lake Candlewood Diversion,” the proposed diversion from Candlewood Lake would include a pump station and intake on the shore of the Lake, a discharge pipeline and an access road.

Storage for the diverted water would be in Danbury’s Margerie Reservoir. The new pipeline would be about 4,750 feet in length. Its cost in 1986 dollars was estimated at $2,240,000. The shortest route with the easiest slope was used.

7. 1986 NEW FAIRFIELD POLICY POSITION:
Danbury has two options for water supply from the north, the Ball Pond Brook Diversion or Candlewood Lake Diversion. The City's northern neighbor, the Town of New Fairfield, has commented upon these proposals in the past.

An excerpt from a September 1986 statement by the New Fairfield Board of Selectman on this issue stated: "While the communities of New Fairfield and Danbury have been negotiating for several years on this proposed diversion, the New Fairfield Board of Selectmen does not recognize the diversion of Ball Pond Brook as either the most desirable or the easiest to implement of the alternatives available for increased water supply."

Continuing, "The most desirable water supply source for the entire region appears to be Lake Candlewood. Since the Ball Pond Brook diversion may ultimately require permits from federal power regulatory agencies, environmental impact analysis, and approval from Northeast Utilities, implementation does not appear to be either immediate or easy. We strongly endorse the selection of Lake Candlewood as the prime water supply source for the region."

8. 1988 REGIONAL WATER UTILITY PLAN:
The state created Housatonic Water Utility Coordination Committee for the Greater Danbury Area, operating under state authority and funded by the CT Department of Health, in 1988 included a Candlewood Lake diversion in its plan as a “potential future water supply source.”

9. 1997 HVCEO REGIONAL PLAN:
It was voted to reaffirm the role of the Candlewood Watershed as a potential future public water supply watershed, continuing the policy adopted by HVCEO in 1972 and supportive of regional water supply needs.

10. 1999 CONSERVATION RESTRICTION
A conservation restriction dating from 1999, negotiated with and owned by the five adjacent municipalities, provides some permanent protections for the Lake should it ever be sold to a non-power producer, and thus fall outside federal jurisdiction. Of relevance to future water supply yield calculations is the key provision that the owner shall not lower the water level below the 418 contour line, except for very limited exceptions such as safety, maintenance and power emergency.

View from New Fairfield across Candlewood Lake looking
east towards Brookfield. Photo courtesy of Rick Gottschalk.

11. 2003 DANBURY WATER SUPPLY PLAN:
According to Danbury’s 6/2003 Water Supply Plan, “two surface water sources, Ball Pond Brook Diversion and Lake Candlewood Diversion, have been identified by the Danbury Water Department as future sources of supply which will be required to meet future demands of the City.”

Continuing, “Lake Candlewood Diversion would consist of a pump station to divert raw water from Lake Candlewood to Margerie Reservoir via a 30-inch pipeline. This diversion would have a capacity of 15 million gallons per day at a 240-foot static head. Assuming Margerie Reservoir was raised and the Ball Pond Brook Diversion in operation, the safe yield of the system would be raised by 6.9 million gallons.

Lake Candlewood has a watershed of about 40 square miles and a storage capacity over 44 billion gallons. Margerie Reservoir, if not previously raised for Ball Pond Brook, would have to be raised three feet to provide an additional 267 million gallons of storage capacity in the reservoir.

Without the Ball Pond Brook Diversion, the additional safe yield would be about 5.3 millions gallons per day. Per Department of Public Health regulations, this diversion could only be operated between Labor Day and Memorial Day, i.e., during the non swimming season.”

Continuing, “an alternative to pumping directly from the Lake would be the construction of a Ranney radial collector well system.

The well system would consist of a reinforced concrete caisson with pumps and motors, which would be installed near Lake Candlewood. Horizontal screens would radiate from the central caisson collecting water from Lake Candlewood by induced infiltration.”

Also available is this critical element of the 2003 Danbury Water Supply Plan: “Lake Candlewood is designated as a Class “B” source because it receives water pumped from the Housatonic River for hydroelectric power generation. The Housatonic River has a Class D rating with a goal of Class B. At one time DEP had considered giving the lake two classifications, Class B near the area of the hydroelectric plant discharge, and a Class A to the rest of the lake.

This approach has not been implemented because of the difficulty in identifying the portions of the lake where water quality is affected by the hydroelectric plant discharge and the effects that future land use patterns would have on the classification boundaries.

The concept of establishing differing classes of water within the Lake remains a valid one and has not been eliminated from consideration by DEP. The land use in the watershed for Lake Candlewood is considered primarily in the low and moderate risk categories for contamination to the reservoir.”

12. 2003 TEXT FROM FERC EIS:
During 2003 the Federal Energy Regulatory Commission issued a draft Environmental Impact Statement concerning the license application by Northeast Generation Services Company for the operation of Candlewood Lake. The statements below are taken from that document.

“During low flow periods in the Housatonic River, pumping activities are curtailed when flows fall below 498 cubic feet per second at Rocky Rive r... Generally, however, water is pumped from the Housatonic River into Candlewood Lake during off-peak hours, to be used for generation during peak demand periods.”

“NGC indicates that pumping operations to refill or ‘recharge’ Candlewood Lake primarily occur during the spring high flow period, and on other infrequent occasions during the evening hours. Staff acknowledge that diversion of 162.6 million cubic feet (6 percent of Candlewood Lake inflow) for water supply purposes could hinder replacement of Candlewood winter drawdown volumes for NGC in dry years.”

13. 2004 FERC LICENSE TO NGS FOR OPERATING LAKE:
On 6/23/2004 the Federal Energy Regulatory Commission issues an updated license to the Northeast Generation Services Company for the operation of Candlewood Lake. As this permit discusses water level and withdrawal issues, these permit conditions will be relevant to any future withdrawals for public water supply purposes.

The license notes that the Rocky River Project “is a pumped storage development which uses the Housatonic River as its lower reservoir and the 5,600 acre Candlewood Lake as its upper reservoir.. Pumping is curtailed during low flow periods, and Candlewood Lake fluctuates up to three feet during the summer and can be drawn down as much as 12 feet during the winter.”

Continuing, “The licensee shall operate Candlewood Lake levels between elevations 425.1 and 427.6 feet National Geodetic Vertical Datum (NGVD) during the summer recreation season (Memorial Day through October 15) with a winter drawdown to an elevation no less then 416.1 feet NGVD for weed control in alternating years and to elevation 422.1 feet NGVD in the alternate years." {HVCEO Note: NGC owns all shoreland up to elevation 440}.

Also, "The Candlewood Lake operating levels specified above may be temporarily modified if required by operating emergencies beyond the control of the licensee, and for short periods upon mutual agreement among the licensee and the Connecticut Department of Environmental Protection and U.S. Fish and Wildlife Service..."

Continuing, "The pumping of the Housatonic River at this development shall be limited to when the stage of the {Housatonic} River at the development is above 196.4 feet NGVD (National Geodetic Vertical Datum).”

{HVCEO Supplemental Note: A minimum elevation figure of 196.4 for the Housatonic River if pumping from it up to Candlewood Lake is to be allowed is of interest. If should be noted that downstream from the Rocky River intake is the low-head Bleachery Dam, which has a crest elevation of 196.0 NGVD. Thus the Bleachery Dam acts as a hydraulic control for the reach of the Housatonic River upstream that includes the Rocky River intake.

From the Bleachery Dam south the next dam downstream is the Shepaug Dam, forming Lake Lillinonah. Lake Lillinonah elevations range from 193.8 feet to 198.3 feet NGVD, above the 196.4 cited above. Thus the backwater from Lake Lillinonah can on occasion inundate the Bleachery Dam, but only at the upper end of the Shepaug Dam's operating range}.

14. DANBURY WATER DEPARTMENT STATEMENT OF 10/2004:
In October of 2004 the Danbury Water Department released a statement defining its upcoming activities in pursuit of Candlewood Lake as a water supply.

According to that statement "The Danbury Water Department (DWD) is looking to our future water supply needs and considering the water supply needs of the region. We anticipate taking the following action steps regarding the use of Candlewood Lake as a permitted water supply. The steps may run concurrently, or be adjusted in sequence as needed:

--- 1. Meet informally with CT DEP and CT DPU staffs to discuss potential (2003).
--- 2. Address letter to Housatonic Water Utility Coordinating Committee to determine interest regarding interconnections with the DWD as part of the water supply planning process.
--- 3. Begin dialogue with the Northeast Generating Company (NGC) concerning use of Lake water.
--- 4. Begin dialogue with the Candlewood Lake Authority.
--- 5. Review concept with area town's chief elected officials.
--- 6. Update CT DEP and CT DPH on progress of discussions and determine if they have concerns.
--- 7. Collect and analyze detailed water quality data as part of a study to determine upgrades required for diversion and treatment.
--- 8. Upgrade the Danbury Water Supply Plan based upon needs analysis and water quality study.
--- 9. Obtain concurrence in form of supporting resolutions, or actions from various agencies to include in diversion permit application and funding applications if available.
--- 10. Begin design of upgrades.
--- 11. Obtain CT DEP and CT DPH approval of diversion and design of upgrades.
--- 12. Begin construction and start up."

And then concluding, "along the way, we will have to be reviewing the financial impacts of the project and some changes may be needed."

15. DANBURY WATER DEPARTMENT STATEMENT OF 4/2005:
As requested by New Milford, the Danbury Water Department clarified on 4/22/2005 that step nine above would include a review of the environmental impacts of the Candlewood Lake diversion upon the Still River and the Housatonic River. This will include research as to changes in sewage effluent flows and water quality impacts from a broad perspective, well before any decisions are made.