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Saturday, November 17, 2012

Dilution of Specific Electrical Conductance

A pattern that is emerging around New Hampshire is that specific electrical conductance is highest at low flows and becomes diluted as flows increase. This is because there are higher solute concentrations in soil water or groundwater and lower solute concentrations in rainwater. Higher solute concentrations in groundwater or soil water are partly natural, caused by dissolution of naturally occurring minerals. However, sometimes higher solute concentrations are elevated by human inputs of minerals, particularly sodium chloride as road salt. Natural or human-caused, this dilution pattern can tell us about how much groundwater contributes to a stream. But, I will leave this discussion to Ashley Hyde for another time. In the meantime, here is a picture of dilution from a downstream reach of the Israel River (or Israel's River). I am writing code to produce these pictures for each site, and this is the first picture I've been able to pull together. I was excited, so I thought I would share.

Monday, November 12, 2012

Our Locations as of Now

This is our map of water sensors across New Hampshire as of October. Each dot is one site; often two sites very close to each other are indistinguishable. A list of sites with names, hosts, and a brief description is forthcoming.

Monthly Conductivity Graphs

We are building computer code (R is our preferred scripting language) to summarize the huge amounts of data arriving from the LoVoTECS sensors. We are going to publish graphs here to share interesting patterns in the data. Here are a few months.

July 2012

August 2012

September 2012 

There is a clear positive relationship between monthly median water temperature and specific electrical conductance. Our warmer streams have more solutes in them - the role human activities play in driving this pattern is a future question that we will be addressing.