NH DES Lake Trophic Survey Program

David Neils Director, Jody Connor Limnology Center NH DES [email protected] (603) 271-8865 History

• Initiated in 1975 to provide basic information about NH Lakes and Ponds

• 40 – 50 lakes / ponds sampled annually

• From 1975 – 2008 ~800 lakes & ponds sampled, ~1,400 total surveys

• Each lake assigned a trophic class-rating (oligo-, meso-, eutrophic)

• Annual report issued that included data from each lake

• Data serves as basis for establishing historic trophic class, statewide analysis of lake water quality, satisfy public requests for data on individual waterbodies

• Lakes sampled once during summer and once the following winter Example of Annual Report & Individual Waterbody Data

Blaisdell Lake, Sutton 2005/06 Blaisdell Lake Report 2005 (con’t)

Trophic Rating

Accessory Data Example: Depth Maps NH DES Trophic Class Rating System

1) Summer Bottom Dissolved Oxygen 0 – 6 points

2) Summer Secchi Disc Transparency 0 – 6 points

3) Aquatic Vascular Plant Abundance 0 – 6 points

4) Summer Epilimnetic Chlorophyll a 0 – 6 points

20.7% Statewide Breakdown of 30.6% Eutrophic Best Trophic Class Rating Mesotrophic Oligotrophic 48.7% Program Discontinued in 2008

...... created problem with aging data Re-institution of Program in 2013 Part of updated NH DES comprehensive surface water monitoring strategy

Up to 10 waterbodies sampled / year

Synoptic Monitoring

Description: Sampling event(s) within a defined time period to complete collect basic water quality information about a specific waterbody.

Approach: Targeted selection of waterbodies based on a statewide watershed (HUC10) approach utilizing a rotational design Updated Lake Trophic Survey Program Overview

What’s different about the program?

• Waterbodies sampled during summer months only (no winter sampling)

• Sampling completed each summer for 3 years (rather than single year)

• Waterbodies selected for sampling based on schedule of target watersheds

• Pre-field season meetings held to select waterbodies

• Updated bathymetric / plant survey methods

Staying the same:

• NH DES trophic rating system

• Most physical, chemical, biological parameters

• Production of individual lake reports the following the last year of data collection Sampling Schedule Progress to Date

2013 2014

• Lake Francis, Pittsburg • Durand Pond, Randolph • Sondogardy Pond, Northfield • Cedar Pond, Milan • Mountain Pond, New Ipswich • Daniels Lake, Weard • Island Pond, New Ipswich • Bailey Pond, New Boston • Oliverian Brook Pond, Benton • Baxter Mill Dam Pond, Rochester • Lily Pond, Gilford • Upper Wilson Pond, Swanzey • Loon Pond, Lincoln • Wilson Pond, Swanzey • Little Pond, Webster • Surry Mtn. Reservoir, Surry Upcoming Field Season

HUC 10 Drainage Name

104000103 Aziscohos Lake Drainage

108010102 Headwater Tributaries

106000202 Swift River

107000102 Upper Pemigewasset River

107000202 Winnipesaukee River

107000602 Soucook River

108010404 Connecticut River-Ompompanoosuc River to White River

108020202 Lower Millers River Reporting

• Reporting is based on a 10 year cycle

• Cycle # 1 will cover 2013 – 2022

• ~80 lakes/ponds will be included

• Report will be published in 2024

• Individual reports available following completion of 3 year sampling cycle