NHDES Lake Trophic Surveys from 1975 - 2010

This program was initially established in 1975 in order to identify the trophic state of NH lakes and ponds, as required by Section 314(a) of PL 92-500 (the Federal Water Pollution Control Act Amendments of 1972). The purpose of the program is to determine lake trophic class and monitor physical, chemical and biological water quality parameters. Each year, 40 different lakes and ponds are surveyed, once in the summer and once in the winter. The surveys are comprehensive physical, chemical and biological surveys, including electronic depth soundings, macrophyte identifications and abundance ratings, shoreline bacteria sampling and at the deep spot a temperature/dissolved oxygen/percent saturation profile, Secchi disk transparency reading, samples for chlorophyll, Ca, Mg Na, and K in the upper water layer, phytoplankton and zooplankton net hauls for identification and counts and discrete water samples at two or three depths for pH, acid neutralization capacity, apparent color, conductivity, TP, Total Kjeldahl nitrogen, nitrite+nitrate nitrogen, chloride, and sulfate. The surveys are designed to assess current baseline conditions and compliance with water quality criteria, identify the lake’s trophic status, determine acid rain impacts and the existence of exotic aquatic plants and provide information for gross long-term trend analyses. See NH_STATION_REPORT for geographic and lake information本项目最初设立于1975年，旨在响应《公法92-500》（1972年联邦水污染控制法修正案）第314(a)款的要求，对新罕布什尔州（New Hampshire，NH）的湖泊与池塘营养状态进行识别。 本项目的核心目标为确定湖泊营养等级，并持续监测水体的物理、化学及生物水质参数。 每年将对40处独立的湖泊与池塘开展两次调查，分别于夏季与冬季各实施一次。本次调查为综合性的物理、化学与生物调查，涵盖以下内容：电子水深测量、大型水生植物（macrophyte）鉴定与丰度评级、岸线细菌采样；在深水区开展温度/溶解氧/饱和度百分比剖面测定、塞氏盘（Secchi disk）透明度读数；采集上层水体样本以检测叶绿素、钙（Ca）、镁（Mg）、钠（Na）及钾（K）含量；通过浮游植物网与浮游动物网拖网获取样本，用于种类鉴定与计数；在2至3个不同深度采集离散水样，以检测pH值、酸中和容量、表观色度、电导率、总磷（TP）、凯氏总氮（Total Kjeldahl nitrogen）、亚硝酸盐+硝酸盐氮、氯化物及硫酸盐。 本次调查旨在评估当前水体基准状况与水质标准合规性、明确湖泊营养状态、判定酸雨影响及外来水生植物的存在情况，并为宏观长期趋势分析提供数据支持。有关地理与湖泊的详细信息，请参阅NH_STATION_REPORT。