2018 Hydrologic Data Summary for the Central Pine Barrens Region, Suffolk County, New York (ver. 2.0, February 2024)

This document provides a summary of surface water-quality, streamflow, and groundwater data collected by the U.S. Geological Survey (USGS) within the Central Pine Barrens (CPB) Region of Suffolk County, New York. The data were collected in cooperation with the Central Pine Barrens Commission and the Town of Brookhaven under a five-year comprehensive water resources monitoring program.

The surface water-quality data within the CPB for the 2018 water year (October 1, 2017 to September 30, 2018) includes data from the Carmans River and the Peconic River. The streams were sampled several times throughout the year at seven pre-determined locations. The Carmans River was sampled at five locations: 1) CARMANS RIVER AT MIDDLE ISLAND NY (01304990; Bartlett), 2) CARMANS RIVER NEAR YAPHANK NY (01304995; Upper Lake), 3) CARMANS RIVER BELOW LOWER LAKE AT YAPHANK NY (01304998; Lower Lake), 4) CARMANS RIVER AT YAPHANK NY (01305000; Carmans Gage), and 5) CARMANS RIVER AT SOUTHHAVEN NY (01305040; Tidal). Site locations Upper Lake and Carmans Gage were sampled four times throughout the year (fall, winter, spring, and summer) while Bartlett, Lower Lake, and Tidal were sampled once (summer). The Peconic River was sampled at two locations: 1) PECONIC RIVER NEAR CALVERTON NY (01304440; Connecticut Ave) and 2) PECONIC RIVER AT RIVERHEAD NY (01304500; Peconic Gage). Each site was sampled twice throughout the year (fall and spring). Field measurements were taken at each site visit. All samples include an analysis for nutrients (SH1865), major inorganics (SH2710 and SH2750), and alkalinity (LC2109). Three sites (Connecticut Ave, Peconic Gage, and Carmans Gage) were sampled for pesticides(SH2437) and pharmaceuticals (SH2440). These data are available in this data report as well as the USGS National Water Information System: Web Interface (NWIS).

In addition to surface water-quality, groundwater-quality data were collected from seven wells at various locations within the CPB. Each well was sampled once during the summer, and analyzed for nutrients (SH2755), major inorganics (SH2701), volatile organic compounds (SH4437), pesticides (SH2437), pharmaceuticals (SH2440), and per- and polyfluoroalkyl substances (PFAS). These groundwater data are not included in this data report but will become available on USGS NWIS as they are reviewed and approved (https://nwis.waterdata.usgs.gov/usa/nwis/qwdata).

Streamflow for the Carmans River and the Peconic River was measured at the seven sites listed above, and at two additional sites for the Peconic River. Each stream has a continuous-record streamflow station (01305000, 01304500) with water-stage-gaging equipment. These data are reviewed and available in NWIS (http://waterdata.usgs.gov/nwis) and WaterWatch (http://waterwatch.usgs.gov).

Groundwater data-collection intervals used by the USGS on Long Island generally are: (1) annual, which provides data needed for statistical studies and model calibration; (2) monthly, which provides data needed for water-availability, saltwater-intrusion, and groundwater/surface-water interaction studies, seasonal-trend analysis, and drought and flood monitoring; and (3) continuous-recording or real-time, which provides data needed for short-term trend analysis, recharge and tidal-variation studies, local groundwater-withdrawal monitoring. In the CPB, groundwater-level elevations are measured monthly by the USGS at 24 wells, and annually at an additional 31 wells. A total of three wells within the CPB are equipped with water-level recorders, which also provides insight into changing locations of stream start-of-flow along the Carmans and Peconic rivers. Of these sites, the CPB commission funded six groundwater wells (405308072553102, S 6413. 2; 405220072493101, S 6441. 2; 404915072531801, S 9129. 1; 405610072562501, S 40853. 2; 405301072415101, S 46542. 1; 405131072455701, S 46546. 1), one of which is a continuous recorder (S 6413. 2). These data are reviewed and available in NWIS (https://waterdata.usgs.gov/nwis/gw) and GroundwaterWatch (https://groundwaterwatch.usgs.gov/).

These water-quality, streamflow and groundwater measurements collected in the CPB region are part of a larger USGS monitoring program that provides information on the hydrologic conditions throughout Long Island. This larger network is funded through USGS cooperation with State, County, and local partners, and provides the information needed for various water management, ecological, and engineering issues, and to produce USGS water-level maps, depth-to-water maps, and hydrological-study reports.