USGS Continuous Nutrient Monitoring in the Mississippi River Basin

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Detailed Description

USGS “supergages” are very complex. Continuous concentrations of nutrients and streamflow are measured at supergages and the information is available to the public in real-time. A network of supergages are very important in the Mississippi River Basin for assessing the changes in the amount of nutrients that are transported to the hypoxic zone in the Gulf of Mexico. By monitoring and analyzing the nutrient data from a regional network of supergages we are taking the first steps in understanding how actions by farmers, industry and governments on the landscape are changing the conditions in the river and the actions we may need to take to preserve this vital resource for generations to come.
 

Details

Image Dimensions: 1280 x 720

Date Taken:

Length: 00:05:48

Location Taken: Mississippi River Basin, US

Transcript

USGS Continuous Nutrient Monitoring in the
Mississippi River Basin video

The Mississippi River is the fourth largest
river in the world and with its tributaries,

the Mississippi drains all or part of 31 States
or about 41% of the continental United States.

This central artery of the US connects the
Great Lakes to the Heartland to the Gulf.

The U.S. Geological Survey is working with
water, industrial, and agricultural groups,

as well as cities, States, Federal and non-governmental
organizations to better understand the river

and monitoring data.

One such collaboration is with mayors of the
Mississippi River Cities and Towns Initiative.

“We are actually a group of 76 mayor's from
Minnesota to Louisiana who have come together

to protect our water way and make sure that
the economies that depend on the river are

more sustainable.

We know in government, especially, what gets
measured, gets managed.

In March of this year, the mayors signed a
memorandum of common understanding with the

USGS and we are working together to deploy
a comprehensive nutrient monitoring network

for the entire Mississippi River Valley.

That might not sound like what would expect
for a group of Mayors and cities but we do

understand that it all starts with water quality.”

The USGS historically has collected both discreet
and continuous water-quality data.

Both discreet and continuous data have provided
a rich foundation of information for science

analyses such as determining trends in water
quality to assess the health of our Nation’s

rivers and streams.

Recent advances in nitrate sensors are now
providing an opportunity to measure changes

in concentration many times per hour or day
and can be deployed in many types of rivers

and lakes.

The USGS has 3,894 real-time stream gages
in the Mississippi River basin that monitor

the flow in the Mississippi and its tributaries.

About 60 sites have continuous monitoring
for nitrates and about 10 sites monitor for

continuous phosphate, but some are temporary
monitoring sites that are deployed for assessing

site specific nutrient issues.

A dedicated long-term nutrient monitoring
or “supergage” network is needed that

will provide a cost effective, consistent,
unbiased regional approach to evaluate the

changes in nutrient loads.

Significant resources are invested by farmers,
industry, and the public to reduce nutrient

pollution to the river and a long-term network
will help us assess the changes that are occurring.

But, setting up and maintaining these continuous
monitoring “supergages” is complex as

Elizabeth Murphy explains.

A USGS “supergage” is a gauge station
with real-time, continuous measurements of

streamflow, other parameters ( such as pH,
Specific Conductance, turbidity, and Dissolved

Oxygen), and at least one chemical constituent
such as nitrate or phosphate.

Discrete samples of nitrate and phosphate
are still collected but the continuous nutrient

sensors help fill in the gaps between samples.

The supergages also collect data when it isn’t
safe to collect discrete samples, such as

during extreme flood events when the largest
loads of nutrients are being flushed through

the basin.

We are here at the USGS supergage to collect
continuous water quality.

This site is on the Green River near Geneseo
Illinois where the station is housed along

the edge of the river.

We can see that nitrate and turbidity are
being continuously recorded at this site from

instruments that are deployed in the river.

Solar power allows these supergages to be
positioned in remote locations.

Integrating cellular and satellite modems
into the supergage also supports remote sites

and allows real-time data upload to the Web
along with remote system monitoring.

(put NWIS web address at bottom of screen).

The long pipes going down to the stream house
the four instruments for measuring nitrate,

phosphate, turbidity, and general water quality.

The USGS makes monthly maintenance trips to
most water-quality sites to clean the sensors

and calibrate them against known standards.

This helps insure that there has been no degradation
to the instrument and the data available on

the web are accurate.

Additionally, the hydrologic technicians collect
samples at the extreme flow events (high and

low) to make sure the instruments are recording
accurately at the extremes.

The largest loads of nutrients to the river
occur during storm and high flow events.

Since the sensors are located at one point
in the river, the technicians will visit the

site for periodic cross-sections of water
quality.

These measurements across the river will allow
us to understand how the measurement at the

instrument relates to variability across the
channel.

By monitoring and analyzing the nutrient data
from a regional network of supergages we are

taking the first steps in understanding how
actions by farmers, industry and governments

on the landscape are changing the conditions
in the river and the actions we may need to

take to preserve this vital resource for generations
to come.