Friday, May 19, 2017

BLOG: Nebraska Groundwater Guru Joins Foundation Board

by Jennifer Wemhoff, The Groundwater Foundation

Jim Goeke at the Platte River near North Platte, 2002
Jim Goeke said he always knew he wanted to be a scientist, but when asked why he chose hydrogeology, his answer was "Thirst." Fall football practices and games throughout high school and college made him appreciate the countless bottles of water needed to sustain him. 

Years later, Jim would become one of the foremost experts on Nebraska's groundwater. He was part of the founding of The Groundwater Foundation in 1985, and last week was elected to the Foundation's board of directors.

"The Groundwater Foundation is thrilled to have Jim on our board," said Groundwater Foundation President Jane Griffin. "As a hydrogeologist, His vast groundwater knowledge, expertise, and experience will be invaluable to the Foundation's mission."

Jim joined the University of Nebraska in 1970, after earning a Bachelors Degree from the University of Wisconsin and Masters Degree from Colorado State University. As a University of Nebraska professor and proud member of the University's Conservation and Survey Division (CSD, the state's geological, water, and soil survey), Jim was responsible for the CSD/U.S. Geological Survey test hole drilling program to delineate the Ogallala Aquifer. Over 1,100 test holes later, he has an intimate familiarity with the Ogallala formation and its water riches. 

According to his biography from the University's School of Natural Resources, Jim's main research interests dealt with groundwater and groundwater management, particularly under conditions of scarcity. He worked to gather data to model unconfined aquifers in the central Platte region and stream-aquifer research in the Republican River Valley. He served as the University's liaison to the Nebraska Well Drillers Association, and worked with USGS on the High Plains Regional Aquifer System Analysis (RASA) and the High Plains National Water Quality Assessment (NAWQA). 

Jim retired from the University in 2011 and became a professor emeritus.

Jim has been active in education and outreach, given countless presentations about Nebraska's groundwater to schools and community groups, and has a long history of involvement with The Groundwater Foundation. In 2001, he received the Maurice Kremer Groundwater Achievement Award from The Groundwater Foundation, among his many accolades.

Wednesday, May 17, 2017

It’s Water-Wise Wednesday with Frannie the Fish! {Awesome Aquifer Kit: Sinkholes}

This week in Frannie’s exploration of the Awesome Aquifer Kit is about sinkholes and how they are formed.

A sinkhole is a hole in the ground caused by the erosion of the soil or bedrock underneath.  They occur when acidic water seeps down and percolates through soluble, or easily dissolved, layers of soil like sandstone, chalk, or limestone.  Over hundreds or thousands of years, more of the rock dissolves while loose soil and sand shifts down to fill the cracks.  For a long time, the land is able to hold its own weight and even the weight of buildings constructed on top of it.  However, as even more of the rock dissolves and becomes empty space, the land becomes too heavy and will collapse suddenly.
For this activity, you will need a pitcher of warm water, sand,
a piece of paper, a cup with a small-medium size hole,
a coffee filter, scissors, and sugar or powdered creamer.
To observe this in our aquifer kits, we’ll start by collecting our materials: a cup, sand, sugar, a paper tube, a pair of scissors, and a coffee filter or sponge.

Frannie starts by cutting a small hole, the same width as the tube, in the bottom of the cup and placing the coffee filter on top of it, keeping it in place with just a little bit of sand.

Next, she puts her tube over the coffee filter and fills the tube a part of the way with sugar.  The sugar represents the soluble rock that will dissolve when the ground gets wet.  While the tube is still in the cup, she pours in the sand so that it comes to about the same height as the sugar.  The sand represents the rest of the ground and will hold the soluble layer in place.



Slowly remove the tube without disturbing the sand or sugar too much and then pour more sand on top, just enough so that none of the sugar is showing.  Carefully pick up the cup and place the bottom into the water and in just a few moments, the water will infiltrate the sand and sugar, dissolving the sugar and creating our sinkhole.

Check out this cool graphic to see what's happening inside the cup!

Graphic by PBS

Wednesday, May 3, 2017

It's Water-Wise Wednesday with Frannie the Fish! [Awesome Aquifer Kit: Erosion and Weathering}

This week in Frannie’s exploration of the Awesome Aquifer Kit is all about the concept of erosion and weathering.

Photo credit: howtosmile.org
Weathering is the slow destruction or wearing away of soil or rock which is followed by the process of erosion, where the broken particles are then carried away.  This is a very important concept for groundwater and it can happen in two ways: mechanical weathering or chemical weathering.

Mechanical weathering is when rock or soil is physically broken down by constant exposure to flowing or moving water.

Imagine a river that’s moving quickly, picking up sand from the beaches and carrying it downstream.  That’s an example of the beach being mechanically broken by the stream, which carries the sand downstream and makes those beaches smaller.  The same thing can happen underground where, as water slowly flows and picks up particles of soil or rock, the land might get worn down and even sink slightly. 
 
Photo credit: USGS
If the sinking of the land occurs over a long period of time, we call that subsidence.

Chemical weathering is when the rock or soil mixes with the water and dissolves to become a new substance.

This usually happens when polluted rain seeps down into a carbonate type of bed rock.  The acidic water comes into contact with the basic soil and changes the chemistry of the rock so that it breaks down and forms new particles that move with the water flow.


Photo credit: ABC News
It is this kind of weathering and erosion that is usually the cause of sinkholes, a type of sudden natural disaster that results with a large hole in the ground.  Frannie will show us more about sinkholes next week.