WSP09054

• File Number: 8407.400
• Description: Platte River Basin - River Basin General Publications - Nebraska
• State: NE
• Basin: South Platte
• Water Division: 1
• Date: 9/1/1968
• Author: Nebraska Soil and Wa
• Title: Nebraskas State Water Plan - Big Blue River Basin
• Water Supply Pro - Doc Type: Report/Study

TABLE 4
SALINITY OF GROUND WATERS IN THE BIG BLUE BASIN*

COUNTY

Adams
Butler
Clay
Fillmore
Gage
Hall
Hamilton
Jefferson
Lancaster
Polk
Saline
Seward
York

LOW
I
o
o
o
o
o
3
o
o
o
o
o
o

MEDIUM
26
II
45
43
10
31
64
8
5
28
10
35
71

HIGH
o
5
o
10
o
17
7
2
4
3
2
I
o

VERY HIGH
o
o
o
o
o
o
o
o
o
o
o
o
o

* No. of samples falling into appropriate USDA classifications based on conductivity.
SOURCE: The Nebraska Water Quality Survey, 1965 Extension Service, etal.

Potassium, calcium, magnesium, sulfur and other essential nutrient elements are present
in substantial quantities in the ground water. When soils deficient in these elements are
irrigated with such waters, fertilization benefits can be achieved. The boron content of the
ground water is generally not high enough to be toxic to plants.

Sodium adsorption ratio (SAR) is used to evaluate sodium or alkali hazard. This ratio is
the sodium content in relation to the magnesium and calcium content. If the sodium content
is high, it will tend to replace the calcium in clay and result in an alkali problem in some soils.
Definite alkali hazards exist in areas of Lancaster, Gage, Polk, Seward, Saline and Butler
Counties.(2) Figure 13 shows the ranges in sodium content of the ground water by county in
the Big Blue Basin.

Some irrigation weils sampled during 1961 contained concentrations of more than 20
ppm nitrate-nitrogen. The wells in the Big Blue Basin showing highest concentrations were
located in Seward and Fillmore Counties. A follow-up study was done in 1962 to determine
the change in nitrate levels. The concentration of nitrate-nitrogen decreased from July, 1961
to August, 1962 in all but one of the original irrigation wells resampled. (12) Nitrogen is a
necessary nutrient for plant growth and can have very beneficial results when it is a~ailable in
irrigation water. However, any nitrate-nitrogen concentration above 10 ppm is considered by
health officials to be unsafe for human consumption. Nitrate-nitrogen concentration of 10
ppm is essentially equivalent to a nitrate concentration of 45 ppm.

A special study was done throughout Seward County during 1960 to 1963 to observe
changes in nitrate-nitrogen concentration and to determine the correlation with fluctuations in
ground water levels.(12) Changes in ground water levels occur each year with the highest levels
normally occurring during the spring. At the end of the irrigation and growing season grou~d
water levels ate usually at their lowest. The study was inconclusive but generally indicated the
nitrate level was highest in the fall following the irrigation'season.

The chemical constitution of the waters of the basin seldom cause serious problems of
corrosion or incrustation.

27