Reservoir EPA Policy Adoption Project (LT2)

City water: clean, pure, safe

Hemlock and Canadice, two pristine Finger Lakes located about 30 miles south of Rochester, supply our primary source of drinking water. The water from these lakes is treated at the Hemlock Lake Filtration Plant before an 18 mile conveyance to Rush Reservoir, located inCobbs Hill Reservoir a non-public, countryside setting several miles south of the city. From there, water is transmitted another 12 miles to the Highland Reservoir and Cobbs Hill Reservoir, both historic landmarks located in public parks within the city. Water is re-disenfected with chlorine as it leaves the reservoirs. 

In 2006, the U.S. Environmental Protection Agency (EPA) required all U.S. communities to change the way they store and treat their drinking water. The EPA regulation, called LT2 (Long Term 2 Enhanced Surface Water Treatment Rule), is designed to protect the country's uncovered drinking water reservoirs from contamination by either natural or man-made causes. Mayor Duffy is committed to ensuring that the City continues to provide the same world-class drinking water that it has since 1876.

In September of 2006, the City hired a consultant to help identify and evaluate alternative methods to meet the new EPA LT2 requirements. Their charge was to help the City find a way to achieve technical compliance at an affordable cost, while at the same time preserving the prized aesthetic value of the reservoirs. A large number of alternatives were studied. Key evaluation criteria included water quality impacts; life-cycle cost (including capital investment and operating cost); affect on system reliability and flexibility; feasibility of construction; and public acceptance. Public education and involvement were key elements of the process.

Study Findings

The initial conclusions of the reservoir study team were that Cobbs Hill and Highland Reservoirs should be preserved in their current visual state, but that large tanks should be constructed on site or nearby for drinking water storage.   Under this plan, water would be kept in the reservoirs, but only for the visual aesthetic appeal. Investigators also concluded that the much less conspicuous Rush Reservoir was a candidate for installation of a large floating cover, a technology that had recently been employed by the Monroe County Water Authority at their Pittsford reservoir. The total estimated cost of the work was $40 million. Residents and community groups were provided with mailings and opportunities to attend public meetings to hear more about, and comment on, the proposed plans. Those with comments and concerns were also invited to submit them online.

Several months after the reservoir study team reached the above conclusions, evidence began to emerge that it might be possible meet the LT2 compliance objectives in a less expensive manner, and without need for the new storage tanks at the Cobbs Hill and Highland sites. The revised approach keeps Cobbs Hill and Highland Reservoirs in service with the addition of a treatment technology called ultraviolet (UV) disinfection. Several of the previously studied compliance alternatives were based on the use of UV treatment, but were rejected primarily on basis of total cost. UV is an energy intensive process and consequently expensive to operate, especially over the long term. In addition, the design assumptions associated with the earlier analysis provided for new on-site structures to house the UV units and ancillary equipment, adding significantly to the overall cost of UV alternatives. In this later investigation, it was concluded that the UV systems could be largely retrofitted into existing structures, saving a large capital (construction) expense, and lowering overall life cycle cost far enough to make this approach more economical than the original preferred option of storage tanks. This revised approach for LT2 compliance at Cobbs Hill and Highland Reservoirs was soon adopted, but the plan for Rush Reservoir (floating cover) remained unchanged.  Under the new plan, the cost estimate for engineering and construction at all three sites dropped to $21 million.

Implementing the LT2 Compliance Plan

HighlandIn January of 2009, the City submitted its plan for LT2 compliance to the New York State Health Department. That plan calls for work to proceed in three overlapping phases, and be complete by the end of 2014. Phase 1, now under design,calls for installation of a waterproof liner inside of Highland Reservoir, and piping improvements at Rush Reservoir. Phase 2 of the plan involves the design and installation of a liner and the aforementioned floating cover for Rush Reservoir. The final phase will be installation of the UV treatment units at Cobbs Hill and Highland Reservoirs. 

Here is a schedule of the key features of the three projects phases:

Phase  1:                           Highland liner/Rush piping 

Phase 2:
Rush liner and cover             

Phase 3:
Cobbs and Highland UV installation 

Design completed

Design completed

Begin Design                  Oct 2011

Construction substantially completed

Begin construction            Feb 2011

Begin Construction          Dec 2012


Completion                       Oct 2012

Completion                    Nov 2014

View the Article 15 NYSDEC Dam Permit Application for Rush project

Mayor Richards is committed to ensuring that the City continues to provide the world-class drinking water to its citizens, as it has since 1876. The plan for LT2 compliance will preserve our historic and much beloved reservoirs while adding an additional level of public health protection that maintains Rochester's proud record of full compliance with all State and Federal drinking water regulations.  

For more information on the LT2 Rule, visit the EPA 

Share your thoughts

If you have questions, comments, or want to arrange a briefing on the Water Reservoir Study for your group or organization, please contact the Water Bureau by email or at (585) 428-7567.