Aerial
Geophysical Survey of Selected Panhandle Aquifers (HEM Survey)
A low-flying helicopter towing a torpedo shaped device
is frequenting the skies over the rural areas north and south of the
North Platte River and around Sidney Draw and Lodgepole Creek in the
southern Panhandle during the week of June 9, 2008. Its purpose was
to collect data that will assist scientists determine optimum ground
water holding capacities in the western Nebraska aquifer.
In April, 2008 the North Platte NRD, in partnership
with the South Platte NRD of Sidney and the United States Geological
Survey (USGS), was awarded an $800,000 Nebraska Environmental Trust
grant. The funding will be used during the next two years to conduct
an aerial geophysical survey of selected Panhandle aquifers located
within the two NRDs. The survey work, which will include flight line
planning and preliminary survey platting, began the week of June 13
and is expected to be completed by June 20.
According to USGS hydrologist and project chief Jim
Cannia, this type of survey will provide important information that
will be far reaching in scope. The survey will provide three-dimensional
maps of the project area, consisting of 270 linear miles to a depth
of up to 300 feet.
“The purpose of this work is to map subsurface geology so we can relate
that to groundwater flow and changes in groundwater quality,” Cannia
said. “We'll get two dimensional drawings of the subsurface with these
flights and that will help us plan future flights to do more high density
mapping.”
The
aerial geophysical survey work will involve the collection of geophysical
data performed by a helicopter flying at a speed of about 60 mph and
height of about 200 feet. The helicopter - provided by the Canadian
offices of Fugro, a geoscience firm - will fly back and forth over strips
of ground one-sixth mile wide with the sensor hanging approximately
100 feet below. This electro-magnetic (HEM) sensor sends electromagnetic
impulses into the ground that bounce back in different intensities based
on the material underground. The varying readings allow researchers
to develop a three-dimensional view of the subsurface.
Approximately 1200 linear flight kilometers of geophysical
data will be collected, including 750 kilometers in the North Platte
NRD and 500 in the South Platte NRD. The total area covered will be
270 linear miles and include nine cities and villages. The USGS Nebraska
Water Science Center and USGS Crustal Imaging and Characterization Team
are performing this work in cooperation with the North Platte and South
Platte NRDs.
Once the data is collected, it will be processed
into the 3-D resistivity data and accompanying maps. Completion of the
interpretation and modeling of this data and the production of maps
and desired GIS databases is planned for June, 2010.
Nine
Mile Creek Restoration Project
Nine Mile Creek, located in the eastern half of the
Scotts Bluff County North Platte River Basin, is classified as a Class
A cold-water stream. A large portion of the stream (approximately
13 miles) is considered trout habitat with natural reproduction of both
rainbow and brown trout occurring. Nine Mile Creek receives its
water supply from five basic sources: naturally occurring ground water,
runoff in the watershed, ground water recharge, direct releases from
three existing irrigation canals that cross the stream, and several
tributary streams. The project implementation along Nine Mile
has become a model on a statewide and national level, and many of the
best practices and standards in invasive species control were originated
through the efforts there.
In 2002 the North Platte NRD received Environmental
Trust funding to begin the Nine Mile Creek Restoration Project. Watershed
coordinator Dennis Beyer was hired and the Nine Mile Creek Watershed
Council consisting of local landowners was formed. A management plan
was put into place that has resulted in the Nebraska Environmental
Trust Fund awarding $410,000 to secure approximately 450 acres of riparian
buffer strips along the streams in the watershed. This has
addressed lotic wetlands by assuring that the buffered area will not
be disturbed by livestock encroachment.
The US Environmental Protection Agency awarded
the Nine Mile Creek Project a grant of $80,900 to eradicate invasive
species in the watershed. This part of the management plan is
still in effect. The Russian olive trees have been removed, spraying
to control noxious weeds in ongoing, and Salt cedar trees have
been foliage sprayed.
The results, after three years, were very encouraging.
It has been determined that with three more years of constant attention
to controlling re-growth of Russian olive sprouts and eradicating any
new growth of noxious weeds, the "Rehabilitation of Nine Mile Creek"
will be a major success.
The North Platte NRD paid to have an award-winning
video produced chronicling the history, farming practices, and changes
that are found within the watershed. To obtain a copy
of this nationally-recognized video, "The Hope of Nine
Mile," please contact
Dennis Beyer at the High Plains Weed Management Association.
