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SHEPAUG RIVER WATERSHED
EXISTING NORTH END DIVERSION
While it is the potential South End Diversion that is of interest to the Housatonic Valley Region's communities, the existing North End Diversion needs to be understood so that the two are not confused.

The City of Waterbury has pumped water from a northern segment of the Shepaug River to its reservoirs since 1921. Waterbury's water interests are shown on a Map of the Waterbury Water Supply System. Of the Shepaug River Watershed's total area of about 150 square miles, about 38 have been in use by Waterbury these many decades as existing public water supply watershed.

Importantly, the Waterbury withdrawal is upstream from the point where the Bantam River empties into the Shepaug River, adding in at that point sewage effluent from the Town of Litchfield sewage treatment plant. As such mixing of sewage into potential water supply is not allowed by Connecticut's water quality laws, this discharge inhibits the viability of a future South End Diversion of water to Fairfield County communities.

Yet state policy continues to protect both the watershed area of the existing Northern Diversion and well as the potential Southern Diversion explained below, declaring the northern 38 square miles to be existing water supply watershed and the southern 112 square miles to be potential water supply watershed. To the land area of both segments CT DEP applies its strict GAA groundwater quality designation.

SHEPAUG RIVER WATERSHED
POTENTIAL SOUTH END DIVERSION
Origin of South End Potential Water Supply Designation: When the first State Conservation and Development Policies Plan was issued in 1973, the Southern Diversion was tied to the construction of a large dam and reservoir on the Shepaug River in Roxbury (see map below). This concept was soon revised in favor of a pumped withdrawal from the existing River, with no dam or reservoir, thus offering less water yield, but also far less disruption.

In Roxbury (RX) above the large blue object is a proposed
reservoir on the Shepaug River, as shown on this excerpt from
the 1973 State Plan. Later versions of the Plan removed the reservoir,
but maintained the future public watershed designation in Roxbury,
Washington (WA), Bridgewater (BW) and New Milford (NM).

It was proposed in 1976 by HVCEO consultant Roald Haestad, Inc.that water from the Shepaug could be diverted to areas of need in both the Housatonic Valley and coastal cities such as Stamford (see map of conceptual diversion route).

But the appeal to the coastal areas was reduced significantly in the 1980's due to a revised relationship between the coastal utilities, with Stamford and Bridgeport able to coordinate supplies under the Aquarion Water Company.

And it would be difficult for the relatively smaller water utilities in the Housatonic Valley to tap this source with their own resources. Thus the viability of the South Shepaug Diversion proposal at least in the short term has been reduced. And Litchfield waste water allowed into this River by CT DEP remains a critical barrier.

Nevertheless, due to the very long range nature of water supply planning, the continued designation of the Southern Diversion's potential watershed area remains endorsed by state agencies as a potential public water supply source area.

To again point out the conflict, the Shepaug River is currently classified as a B/AA watercourse south of its confluence with the Bantam River tributary in Washington, which allows it to receive wastewater discharges. This makes it unsuitable for use, at least under current law, as a drinking water supply source. But on a more hopeful note the ultimate goal is Class AA, or no discharges allowed and suitable for water supply.

As noted the primary source of wastewater in the River is the Litchfield Sewage treatment plant. If this discharge, along with other smaller ones were removed, possibly diverted easterly at great expense to the Naugatuck River, the southern Shepaug thru Washington, Roxbury, Bridgewater and Southbury could theoretically be reclassified from B/AA to AA to be fully suitable for public drinking water supply.

Perspective of the Army Corps of Engineers in 1982: The feasibility of diverting the Shepaug River near the Roxbury Falls area through a pipeline 38 miles long was investigated by the U. S. Army Corps of Engineers in 1982. The pipeline proposed would follow major roads to Margerie Lake Reservoir in Danbury, then on to Trinity Lake in New York State, and finally to the Bargh Reservoir in Stamford.

Under this plan, water from the Shepaug River would be diverted during the wet months of December through May only. A maximum diversion of 11 million gallons per day was evaluated for use by need areas.

There are many different types of diversion structure that could be built to handle this quantity of water. If the inlet is located at a proper elevation along the Shepaug River, the Corps Study noted that a sill across the river to keep out Lake Lillinonah water would not be required.

When discussing the diversion of water from the Shepaug River, the segment of the River most affected would be that situated directly below the diversion. In this case, the Shepaug River flows from an elevation of 210 feet at the potential diversion site near Minor Bridge Road until it levels off downstream in Lake Lillinonah at 195 feet, a distance of approximately 2000 feet. Included within this short stretch is a series of small rapids which make up the lower end of Roxbury Falls.

Shepaug River photo courtesy of HVA

The Corps noted that this is a very aesthetically pleasing area that may be adversely affected by a diversion of water above this point. The flooded section of the Shepaug River (an northward arm of Lake Lillinonah) then extends 3.7 miles downstream to make the entire diversion impact area approximately 4 miles.

Others have since suggested that It would be preferable to have a future tap on the Shepaug, if ever needed, be built well downstream of Roxbury Falls, thus eliminating potentially negative impacts in that area. This River in its entirety is considered a pristine scenic resource.

With a diversion there would be less Shepaug water entering Lake Lillinonah and the impact of this upon fisheries, wildlife, recreation and power generation would need to be determined. Also, any diversion would need to be made during the high flow season when the current owner, Northeast Generating Company is in the process of releasing excess water.

Endorsement by the Housatonic Water Utility Coordinating Committee (WUCC): Designation of the southern Shepaug as a long range future water supply resource was endorsed by the Housatonic WUCC in its 1988 plan entitled "Integrated Report for the Housatonic Water SUpply Management Area.

Coordination with State and Town Plans: Since 1973 the State Plan Map for Bridgewater has maintained the strict AA and GAA designations for the Shepaug Watershed in eastern Bridgewater. The same policy is applied to eastern New Milford on the State Plan Map for New Milford.

These designations generally discourage the introduction of sewers and dense development, but do not restrict single family development on large lots, as is planned in these areas.

As for coordination with town plans, as an additional environmental conservation measure, the 2001 Bridgewater Plan of Conservation and Development recommended the implementation of additional buffer zones along Lake Lillinonah and the Shepaug River. Then as a second step, the additional buffers are proposed to extend inland, to all of the watercourses and wetlands comprising the Shepaug River Watershed in Bridgewater.

About one third of Bridgewater, the eastern portion draining easterly to the Shepaug River, would be affected by this additional watershed wide regulation. This area of Bridgewater is primarily zoned for low density residential uses.

To the north, New Milford has the same geographic situation, with the eastern portion draining easterly to the Shepaug River. As in Bridgewater zoning is low density residential.

The 1997 New Milford Plan of Conservation and Development declares itself consistent with the State Plan's conservation designation for New Milford’s Shepaug Watershed. But in contrast to Bridgewater, an additional regulatory effort for New Milford’s portion of the Shepaug Watershed, which is estimated at somewhat less than 10 % of the Town’s total area, is not proposed by the 1997 Plan.

Then the 1999 Roxbury, CT Plan of Conservation and Development makes no mention of the concept of diverting some of the Shepaug River’s waters to the south. However, in the Roxbury Wetland Regulations, the Shepaug Watershed does get some special treatment.

That is found in the definition of regulated activity, which includes certain activities that take place within 200 feet of the Shepaug River, 100 feet of any another watercourse, or 100 feet from any wetland.

SHEPAUG RIVER WATERSHED
WATER SUPPLY STATUS AS OF 2006
As noted above, within state water resource planning the Shepaug River Watershed in Bridgewater and New Milford remains designated as a potential water supply resource. The HVCEO regional plan also makes this recommendation.

As an update for its revised regional plan, the following overview of potential use of the Shepaug River Watershed for water supply use was developed for the HVCEO in 2006 by noted water supply expert Donald Smith of Roald Haestad, Inc. of Waterbury, CT:

"The Shepaug River is a Class B stream with a goal of AA. Treated sewage discharges in Litchfield are the reason for the Class B water quality. The river has been considered as a future water supply source for many years. Under current Department of Public Health policy, Class B rivers can be included in water supply planning studies, but can not be used for pubic water supply.

The State’s 1973 Plan of Conservation and Development identified the Shepaug River as a potential source with a pumped diversion just above its confluence with the Housatonic River.

The Shepaug River has a tributary watershed of 155 square miles at its confluence with the Housatonic River. This would provide a substantial yield as long as storage was available.

The 1973 proposal was to construct a low weir across the Shepaug River downstream of Roxbury Falls. The weir was to prevent Housatonic River water from entering the diversion. High flows and all flows, if the diversion were not operating, would spill over the weir to the Housatonic River. A pump station would be constructed on the shore with a 36-inch pipeline across the Housatonic River to the watersheds of existing water supply reservoirs.

This diversion location would not interfere with recreational use and aesthetics of the Shepaug River, but would protect the river from future sewage discharges.

The estimated yield of the diversion was up to a maximum of 50 MGD, and could serve Bethel, Danbury, Aquarion Water Company of Connecticut (including Stamford and Greenwich), and the Norwalk water systems.

It would require relocating the sewage discharges from the Litchfield sewage treatment plants to the Naugatuck River watershed in order to restore the Shepaug to Class AA status.

It is highly unlikely that the sewage discharges will be relocated, so unless the Department of Public Health changes its policy, which is also unlikely, the Shepaug River will not be available for public water supply."

In 2006 a spokesman for the Intergovernmental Policy Division of CT OPM, Planning Specialist Jeffrey Smith, stated in a letter to HVCEO that development of the southern Shepaug watershed for drinking water purposes would be problematic at this point, but such use is not impossible and no formal action has ever been taken to remove the "potential water supply watershed" designation from the state plan.

"Given the situation with regard to drinking water supplies in your part of the state, OPM has had no compelling reason to remove this watershed from its protected conservation designation."