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Hanover, NH, Norwich, VT and neighboring towns

updated 7/27/04     Home Page >> talks at recent League forums

State and Regional Water Issues


Dr. Wunsch spoke on the following topics:

I. NH Geological Survey
Only 3 states, MA, NH, & Hawaii did not have a state geological survey. Having a survey allows NH to be more competitive for federal grants (about $25,000/in 2000) to undertake additional research. NH is getting about 1/4 of what other states are getting. Geological maps return from 25 to 39 times their initial investment cost.

The purpose of his office is to centralize and coordinate geological mapping, to do research on land, mineral, and water resources of the state and disseminate the findings. It is non regulatory, just a data and information source. A statewide bedrock and geological map already exists, but his team does more refined, on-site mapping in each quadrant with particular attentiion to the surficial (mainly of glacial origin) geological deposits.
II Geology, mapping and ground water occurrence in NH
David Wunsch reviewed the water cycle -- from the evaporation of rain from oceans, due to heating by the sun, to deposits as snow and rain, to its penetration of the earth, depending on the soil and bedrock. Groundwater flows to a certain depth where it collects… that’s the water table.

He then described the capacity of different types of soil and rock to contain water and interpreted geological maps of the bedrock complex in NH. Maps used in the presentation can be printed out from the NH Geology web site. Simplified Bedrock Geologic Map of New Hampshire: http://www.des.state.nh.us/pdf/sim_br.pdf

In sand, the spaces between grains create porosity, places where water can be stored. Granite has 1/10 the porosity of sand, at 2% porosity compared to 20%. If there is a fracture in granite, & thus water, it does not always mean that the fractures are interconnected to other larger fractures, so the water supply can be limited.

What about clay? It has high porosity, but one can’t get water out. Clay acts as an impermeable layer.

Metamorphic rock has fractures in it that water can penetrate.

Stratified-drift deposits, which are glacial, lie on top of bedrock and cover 14% of the state. These are aquifers --areas which contain significant amounts of groundwater. Most urban centers occupy areas of stratified-drift, so the future water supply potential may be limited. We’re paving over these aquifers.
III Sustainability
The UN 1987 definition of sustainability :The ability to meet the needs of the present generation without compromising the ability of future generations to meet their needs

To achieve sustainability, we need to

With the aid of a chart David Wunsch described the use of water in NH for:
Thermoelectric power (largest use)

The majority of dams were built between 1950-1979. They are now in decline; we’re tearing them down.

Demand for ground water is rising. The seacoast region experienced the most growth.

(Well yield is a function of total depth for the 28,346 wells in the state. Most wells are between 200-300.' After 300' there is less of a chance of getting significantly more water. Sometimes drilling simply creates a deeper reservoir to store ground water.)

Stream flow conditions vary. The drought last summer produced the lowest month end water level since data started being collected in Nov. 1966.

But there are big unknowns in figuring out how the drought is causing a decline.
What’s going on in the bedrock aquifer? There could be an interconnection of fracture systems in the bedrock, taking water that seemed to be going in one direction in another. But where is it? Sometimes from satellite photos one can discern fractures.
What is the interaction between the surficial aquifer and the bedrock aquifer?
Clays will compress as you pump waters below them, compressing the aquifer.
IV. Water Quality
Common contaminants in NH erode potable water supply
Natural: arsenic, uranium/radon, fluoride
Man induced: pesticides, road salt, organic chemicals, MtBE, an organic chemical soluble in water, bacteria (septic waste), heavy metals

(In KY, and most states as well, septic contamination was sometimes due to bad construction of wells.)

To reduce contamination:
 V. Seismic activities
Generally earthquakes occur along a geological fault. However, in NH they have not been along faults, but lakes -- Ossipee Mt. Range an old volcano.

According to FEMA, Central NH is rated one of the highest risks for damage from earthquakes. There has been a significant e.g. magnitude 6.0 or greater earthquake fairly frequently.

Questions
Having spoken on these topics, Prof. Wunsch responded to questions. Answers to some of the questions may be of interest:

Biggest landfill in US—Interstate highway system, not mines or solid waste landfills

One should keep the pollution caused by mining in perspective . There is less contamination from this source than from more common ones.

There is no state law regulating town wells, though the state keeps a record of all wells dug or drilled. In Hanover, one may not drink water from in-town wells, one but may drill.

Carol Hildreth is mapping in this area.

Is there any state legislation we should be aiming for?
Look at the budget item for geologic mapping. He had proposed a state match for fed. funds.

Where to go to have well water tested?
State of NH tests water samples you provide

If you have old pipes, made of copper, metal or tin you should let the water run early in the a.m., before taking a drink.

What is the potential damage from Calcium Chloride which is used on roads in summer, to hold dust down?
David Wunsch’s view is that it’s less dangerous than sodium chloride. Calcium is important to plants. It is probably not harmful to a pond near a road.

The Conservation Commission has done research in Plainfield, and is supportive of its use.

Herbicides and insecticides sprayed along highways are scarier to him.

Use of artificial (man-built) wetlands?
These are popular in southern states. For acid mine drainage they create recharge basins. Plants and soil are good at decontaminating water of oil and grease.

Aquifer mapping: what is the procedure to get aquifer mapping?
He would be glad to meet with people interested.

Re Groundwater recharge. What is the definition of steep slopes?
UNH Cooperative Extension, staff deals with those issues. Soil Conservation Service may do that as well. To prevent runoff, water bars may be built.

To what extent do his efforts overlap with USGS? 
No overlap: They supply $$ for his projects.

Publications referred to by Dr. Wunsch are listed on the web site, NH Geologic publications http://www.des.state.nh.us/geo1link.htm
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