2005 Winning Projects                                                                              

 Catskill/Delaware UV Disinfection Facility EIS
Mount Pleasant, New York

HONOR AWARD— PLANNING

ENTRANT: Hazen and Sawyer, P.C./CDM
ENGINEER IN CHARGE: Richard Peters, P.E.

Project Description
Under a USEPA Filtration Avoidance Determination (FAD), NYCDEP must build an ultraviolet light (UV) disinfection facility for the Catskill/Delaware water supply, which provides 90% of the water used by its 9 million customers. By building this facility, NYCDEP will avoid the much costlier and disruptive construction of a filtration plant, while providing increased health protection from water-borne pathogens―specifically, Cryptosporidium.

A major step in implementing this project is the preparation of a complex, comprehensive environmental impact statement (EIS), encompassing multiple alternatives and combinations of projects at the selected site, and utilizing innovative techniques for identifying, preventing, and mitigating potential environmental impacts.

Integrated Approach
The EIS entailed detailed evaluations of all potential environmental impacts, including traffic, air quality, noise, and natural resources impacts. Its aim is to minimize or avoid such impacts to the maximum extent practicable by implementing feasible mitigative measures. These impacts were also evaluated for ancillary facilities and unrelated existing and planned facilities onsite. Examples include:

• Any traffic impacts from hauling excavated material for filling/landscaping of the Catskill/Delaware aerators will be mitigated through various measures and, while some trees may be removed during final landscaping, six acres surrounding the aerators will be restored using indigenous meadow grass.
• Mitigation measures for the three acres of wetland habitat to be impacted by construction include restoration of temporary disturbances, enhancement of disturbed/degraded wetlands, and wetland creation. Again, any tree loss will be mitigated and is also addressed in the EIS’ overall natural resources mitigation program. 

Innovation

• Unprecedented Scale: UV is an emerging technology for disinfecting drinking water. The largest UV facility currently in service treats 180 million gallons per day (mgd), while the Catskill/Delaware facility will treat 2 billion gallons per day (bgd) and will be, by far, the world’s largest. The practical application of UV on this scale opens the door for other large utilities to consider UV for their drinking-water facilities.
• Challenging EIS: EIS preparation entailed overcoming a combination of challenges (e.g., large urban client, FAD timeframe, need to accommodate other facilities onsite). The result is a thorough study/evaluation of the environmental considerations associated with constructing such a large facility in a highly developed area, with minimal impacts.
• Technological Advancement: This project represents a tremendous leap forward for drinking-water UV disinfection. Development of the largest UV units to date, each capable of treating up to 40 mgd under worst-case water-quality conditions and possibly 50 mgd under normal conditions, contributes toward economical use of UV technology for cities and large water purveyors, worldwide.
• EIS Roadmap: The EIS should serve as a model to urban clients facing similar challenges in siting and gaining acceptance for large-scale facilities. For instance, the EIS calls for advanced stormwater management techniques based on groundwater modeling. This model evaluated impacts of lowering the water table during (and after) construction on the site’s wetlands, leading to recommendations for enhancement of onsite wetlands instead of engineered stormwater detention basins―an approach the host community prefers. Another example was the use of low-sulfur fuels for construction equipment. Impacts of using these fuels were quantified and addressed within the EIS.
  

Social/Economic Advancement 

• Protecting Public Health: UV provides enhanced disinfection of pathogens, including Cryptosporidium. Ultimately, this project will benefit all residents and visitors to New York via cleaner drinking water.
• Minimizing Consumer Costs: The UV facility’s construction cost is estimated to be about 1/4th that of a filtration plant. Its implementation is expected to increase consumer water costs by only a few dollars per year―an amazing bargain for a city that already offers one of the nation’s lowest water rates.
• Reducing Environmental Impacts: Building a filtration plant would have had larger-scale environmental impacts over a longer construction period than UV. Environmental impacts will be further reduced by the EIS’ innovative mitigation measures. For instance, construction impacts (such as noise and traffic) will be mitigated or minimized. The EIS also includes measures to protect the site’s extensive natural resources (replanting of trees, stormwater BMPs, and wetland enhancement/creation). And the facility’s footprint has been minimized by using a fewer number of the largest practicable UV units, further mitigating environmental impacts.

Complexity
One EIS, Many Components: Not only does the EIS support a groundbreaking project, it integrates a multitude of additional items into the UV project, taking into account other potential projects and combinations of projects at the site and their individual and cumulative impacts.

First, the EIS was not limited to one facility at a given site. It incorporates many components, with new components added as the design and EIS progressed―all without impacting the USEPA-mandated EIS completion schedule. Major additions included pressurization of two miles of Catskill Aqueduct, which, along with the Delaware Aqueduct, feeds the UV facility; provisions for maintaining water supply to users on the Catskill Aqueduct during pressurization; a new 1-bgd screen chamber for the Catskill Aqueduct; and improvements to facilities at the upstream Kensico Reservoir, including filling decommissioned aerator basins and landscaping the area in a manner acceptable to the host community. These items significantly added to the complexity of the EIS, since the engineering associated with each additional item was at a different level of development than that of the overall UV facility. Engineering studies and design efforts for various components were expedited, to ensure that the impacts associated with each item would be comprehensively represented within the EIS without impacting the schedule.

The EIS also addressed other, unrelated onsite projects. Most notably, NYC’s 290-mgd Croton Water Treatment Plant (WTP) was being considered for construction at three alternative sites, one of which was the same site as the UV facility―possibly during the same time period. Since constructing both facilities would involve a greater scale of construction than the UV project alone, consideration of impacts associated with Croton WTP further escalated the EIS’ complexity. Other potential facilities included in the EIS and planned at the same site are a NYCDEP Police Precinct, shafts associated with the future Kensico-City Tunnel, and possible relocation of the historic Hammond House, currently located onsite.