Watershed Monitoring, Modeling, and GIS

FAD Section 5.1 - Watershed Monitoring Program

2007 FAD Requirements

Section 5.1 of the 2007 FAD requires that the City conduct a watershed-wide monitoring program in accordance with Section 2.4.1 of its Long-Term Watershed Protection Program and the milestones therein. The monitoring framework was originally defined by the Drinking Water Quality Control (DWQC) Integrated Monitoring Plan which was finalized by the City in October 2003. This Plan, now called the 'Watershed Water Quality Monitoring Plan' (WQMP), describes the City's hydrology, limnology, and pathogen monitoring and surveillance programs which support trend analysis, modeling efforts, and reservoir operations.

Pathogen reports are provided annually which summarize results at keypoints (Kensico Reservoir intakes) as well as in the WOH reservoirs. Annual updates on ongoing research activities are also provided. The City submits a monthly report which describes its compliance with the objective regulatory requirements for filtration avoidance, such as turbidity and coliform bacteria levels in source water, and disinfection.

As watershed programs and analytical techniques for key parameters evolve, all parties have recognized that it would be necessary to reassess the monitoring program to ensure that it continues to support the City's watershed management program and that it can be used to evaluate the effectiveness of programs established under the FAD and MOA. The 2007 FAD required the City to review the elements of the monitoring program and, based on this review, submit an updated monitoring plan in October 2008.

The City also committed to undertaking a comprehensive evaluation of its watershed protection program on a periodic basis. The last submission on this evaluation occurred on March 31, 2011. The data generated through the City's monitoring program, in conjunction with other defensible scientific findings, will be used to conduct the City's periodic assessment (next due in 2016) of the effectiveness of the watershed protection program.

Evaluation of the NYC Water System's Performance

In accordance with the 2007 FAD, the City has participated in educational seminars on watershed monitoring. The City has held an annual watershed conference each year at the Hotel Thayer in West Point, NY:

  • September 10-11, 2007
  • September 16-17, 2008
  • September 14-15, 2009
  • September 15-16, 2010

The City has also participated in the Annual Ashokan Watershed Conference.

The Pathogen Technical Working Group has convened and discussed pathogen research and detection methods in March of each year since 2008. The last two group meetings were held on:

  • March 31, 2010
  • March 24, 2011

Recent discussions have focused on improved methods for virus recovery and detection at keypoints.

The City discussed the draft contents of their Integrated Monitoring Plan (now called WQMP) with EPA, NYSDOH and NYSDEC and originally submitted the plan on October 31, 2008. After review and comment by NYSDOH and USEPA, a revised plan was submitted in May 2009.

All reporting requirements for this program have been met. Watershed Water Quality Annual Reports were regularly received in July on 2008, 2009, 2010 and 2011. Annual summaries of water quality, water quantity, pathogens, watershed management, model development and potential research are included in this comprehensive report. In addition, all the City's Pathogen Mid-Term Surveillance Reports have been received. The reports, received in January of each year, cover the period July 1 through December 31 of the previous year. Four targets of the water quality monitoring are: 1) Kensico Reservoir perennial streams; 2) wastewater treatment plants; 3) upstream water sources; and 4) watershed pathogen sources. Recent changes have included a shift in the monitoring plan for WOH WWTPs so that newer plants can be monitored (for virus) and those with sufficient data can be removed from the monitoring plan. Special studies have included focused sampling at upstream sites suspected of contributing pathogen loadings and method projects for improved identification of microorganisms. The 2011 Watershed Protection Program Summary and Assessment report covering the first five-year period of the 2007 FAD was received in March 2011 and serves as a reference for this five-year FAD review.

FAD Section 5.2 - Multi-Tiered Water Quality Modeling Program

2007 FAD Requirements

The Multi-Tiered Water Quality Modeling Program is an ambitious effort to link together a number of simulation models that are used to assist in short and long-term planning and decision-making as it relates to both water quantity and quality. Briefly, this process involves using watershed land cover characteristics, climate, and weather data to simulate the quantity and quality of water entering City reservoirs. These inputs are then integrated with reservoir bathymetry, climatically-driven thermal structure, and operational flows to simulate reservoir water quality. Taken all together, this is a powerful water management tool to assist in operational decisions such as controlling the impact of Catskill turbidity on finished drinking water quality, as well as to evaluate potential impacts of climate change on water quality and water supply reliability in the future.

The 2007 FAD requires the City to update and test its models as new data, software, and research findings become available. The modeling program will continue to support the Catskill Turbidity Control Program and serve as a basis for operational decisions made in response to high turbidity events. Modeling efforts will also be used to support other watershed management, reservoir operations, and long-term planning applications.

Evaluation of the NYC Water System's Performance

The Multi-tiered Water Quality Modeling Program has met the requirements of the first five-year period of the 2007 FAD, and continues to be a valuable component of the City's watershed protection program. Data updates appear to be made in a systematic manner as new information becomes available and data management infrastructure improves. As discussed in the section on the Catskill Turbidity Control Program, the City's modeling group has played an important role, through implementation of the OST, in helping system managers to make operational decisions during high turbidity events, thereby reducing the need for alum treatment.

All reporting requirements of this program have been met. The report on the Phytoplankton Functional Group Model Application to Cannonsville Reservoir was submitted. This report indicates that the Phytoplankton Functional Group Model predicts general shifts in functional groups fairly well, and will be useful in climate change planning. This work has been continued, with a one year extension being given to the Upstate Freshwater Institute to further develop the hybrid UFI-PROTBAS model. In addition, expansion of the Nutrient Management Eutrophication Modeling System capabilities to the Neversink, Rondout, West Branch, Ashokan, and Schoharie Reservoirs was completed in 2007.

FAD Section 5.3 - Geographic Information Systems

2007 FAD Requirements

The City utilizes an extensive Geographic Information System (GIS) in its watershed protection efforts. In addition to creating maps and illustrating environmental data; GIS is also used in data gathering, satellite imagery analysis, and complex environmental modeling. A few of the key areas where GIS plays a vital role include: land acquisition and management, Catskill turbidity control, water quality modeling, watershed protection evaluation, water system operations for system reliability and maximizing water quality, and long-term planning. Overall, there are few FAD programs where GIS is not used in some way.

The 2007 FAD requires the City to continue to maintain and update its GIS capabilities, and to report on use of GIS, GIS updates, and dissemination of GIS data to stakeholders as needed.

Evaluation of the NYC Water System's Performance

The City continues to have a robust and active GIS program, and has made the updates and improvements necessary to effectively use this technology in their watershed protection efforts.

Numerous acquisitions and improvements have been made to GIS data layers and infrastructure during the first five-year period of the 2007 FAD. High resolution areal satellite images were acquired and many updates and enhancements were made to existing data layers used in terrestrial data analysis and various aspects of land management, as well as to FAD activity tracking data storage and utilization. The GIS library was migrated to an improved platform which improves system performance and saves substantial amounts of staff time.

In addition to serving as an important in-house resource to many programs, the GIS group also shares non-sensitive data with partners, stakeholders, and other interested parties. For example, the City updates communities on newly purchased watershed land holdings. The City also works with the New York State Office of Cyber Security and Critical Infrastructure Coordination and NYC's Office of Emergency Management.

Overall GIS has been and will remain a critical tool in FAD implementation and other aspects of watershed management and water system operations.