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COMPLETION REPORT

Project No. A-049-MONT

GROUND WATER SEEPAGE AND ITS

EFFECTS ON SALINE SOILS

MUJWRRC Report No. 66

STATE DQCUfv;£NTS

""jAN 2 1 1976

|]

Montana University Joint

Water Resources Research Center

MST|tB25'81

WAY 2 3 1990

MAR1« 1999

'!'«Vl9 20oo

MONTANA STATE LIBRARY
o™u"f«'r/*:ri'^iiii|iniii|i«lll

3 0864 00020123 9

MUJWRRC Report No. 66

COMPLETION REPORT

Project No. A-049-MONT

GROUND WATER SEEPAGE AND ITS
EFFECTS ON SALINE SOILS

MUJWRRC Report No. 66

by

Loren L. Bahls

Montana Environmental Quality Council

Helena, Montana 59601

and

Marvin R. Miller

Montana College of Mineral Science

and Technology

Butte, Montana 5 9701

NOTE: This report was previously published in the Second Annual
Report of the Montana Environmental Quality Council, Helena, Montana.

Montana University Joint Water Resources Research Center

Montana State University
Bozeman, Montana 59715

October 1975

The work upon which this report is based was supported in part by
funds provided by the United States Department of the Interior, Office
of Water Research and Technology as authorized under the Water
Resources Research Act of 1964, Public Law 88-379, as amended.

TABLE OF CONTENTS

INTRODUCTION 1

HISTORY 3

HYDROGEOLOGICAL SETTING 7

POTENTIAL REGIONAL PROBLEM 11

ECOLOGICAL ASPECTS AND IMPLICATIONS 14

Environmental Effects 14

Natural and Agricultural Ecosystems 19

PROSPECTS FOR RETARDATION 22

Farming Practices 23

Nonfarming Practices ^ 28

TENTATIVE RESEARCH CONCLUSIONS 30

RECOMMENDATIONS 35

FUTURE PLANS 36

LITERATURE CITED 37

TABLES AND FIGURES

Figure I: Saline Seep Formation 3

Figure 2; Northern Great Plains Region, Showing Area of

Potential Saline Seep Development. . 12

Table 1: Analyses of Salt and Water Samples in the Fort

Benton Area 16

SALINE SEEP IN MONTANA

by

Loren L. Bahls

Ecologist='=

and

Marvin R. Miller

Hydrogeologist-''*

INTRODUCTION

Saline seeps are recently developed saline soils in nonirrigaged
areas that are wet some or all of the time, often with white salt
crusts, and where crop or grass production is reduced or eliminated. -•*
They are manifestations of 20th century dryland agriculture and the
crop-fallow rotation system necessary for moisture conservation and
small grain production on the scale practiced in Montana. The
widespread occurrence and rapid growth of saline seeps have been
recognized as one of the most serious conservation problems in
the northern Great Plains (14).

A 1971 Soil Conservation Service (SCS) survey revealed that
more than 80,000 acres of nonirrigated Montana cropland had been
lost to saline seeps (6). Serious outbreaks of seep have now appeared
in northcentral and northeastern Montana and are increasing at a
rate of over 10 percent a year. Other estimates show that 150,000
to 250,000 acres of cropland have been lost, and if the acreage of
saline farnrx, recreation, and stockponds as well as badly eroded

'•'Ecologist, Montana Environmental Quality Council, Helena
>;<*Hydrogeologist, Montana Bureau of Mines & Geology, Butte
-••**Definition accepted by Governor's Committee on Saline Seep,
August 30, 1973.

coulees and "seeped" drainageways were included, the affected area
would be much greater. Saline seep is known to be highly destructive
to Montana's soil, water, and wildlife resources, but the true extent
of its adverse environmental effects is only guesswork.

Although aggravated by the crop-fallow system now in use,
the saline seep problem stems from the geology of the northern Great
Plains region. The surface material is glacial till up to 70 feet
thick. The till is underlain by a thick marine shale formation that
is impermeable to water. Both the till and the shale contain an
abundant supply of natural soluble salts. Excess water, evidently
produced by dryland moisture conservation, moves through the till,
picks up salts, and builds up on top of the shale, froming a "perched"
water table. This excess water gradually moves downslope, accumu-
lates in the lower swales, and eventually reaches the surface and
evaporates, leaving the dissolved salts behind (Figure 1).

This paper outlines the history of the development of saline
seep in Montana and efforts to control it; it describes in detail the
hydrogeological setting of the area affected and notes the potential
for spreading throughout much of the northern Great Plains. The
latter portion of the paper deals with environmental aspects and
implications of saline seep, including environmental impact and possible
control technologies.

Fig. I Saline Seep Formation

Precipitation

I

Upland Fallow Field
(recharge area)

Swale(discharge area)

Saline Seep

^T?<

\/v:t>'*.,M

Impermeable Shale

^JKjt-^^Water Table<Os^^

HISTORY

Patches of alkali dotted the northern plains before the white
settlers arrived. Lewis and Clark referred to them in their journals:
"The salts which have been mentioned as common on the Missouri
are here so abundant that in many places the ground appears perfectly
white, and from this circumstance the river may have derived its
name (8). " These spots persist today, mostly on rangeland, but are
apparently nothing more than static, residual salt accumulations from
Sonne natural evaporative process working over geologic time. Unlike

4

present-day seeps, these naturally occuring salt deposits do not spread.
For these reasons they are not included in the definition of saline
seep given at the beginning of this paper.

The saline seep story began between 1910 and 1920 when most
of the native grassland of northern Montana was plowed. Undoubtedly
some excess water accumulated beneath the root zone for many years
following, but extended periods of drought and inefficient farming
practices probably slowed saline seep development. The phenomenon
(locally called alkali or north slope alkali) first appeared in Montana
in the late 1940s, just a few years after the alternate crop-fallow
farming system became well established; after large, high-powered
farming equipment became available; and after the beginning of wide-
spread chemical weed control (7).

Some early accounts show sporadic concern about the problem.
In 1947 the Montana Cooperative Extension Service (MCES) made a
brief field investigation and wrote an evaluation (26). In 1954 an
article titled "North Slope Alkali" appeared in the Montana Farmer
Stockman (29). And, in 1955, prinnarily through the efforts of
R. W. Warden, first district conservationist for the SCS at Fort
Benton, a team of SCS specialists investigated seep areas and
prepared a short report.

The Highwood Bench south of Fort Benton was one of the first
areas in Montana to be affected. Salt accumulation there has become
increasingly serious, with 10,000 to 12,000 acres of nonirrigated
farmland put out of production during the past eight years. It was
not until 1968-69, however, that an organized plan of action was
initiated by several farmers on the bench. The Highwood Alkali
Control Association (HACA) was formed in 1969 with 75 members.
At the association's behest, the Montana Bureau of Mines and Geology
(MBMG), Montana State University (MSU), Agricultural Research
Service (ARS), and SCS have begun to investigate the problem.

To quantify the rates of growth and areal extent of saline seeps
on the bench, aerial photographs of the Nine Mile watershed taken
over a 30-year period were used. Accumulated percentages of the
total land area in the watershed (19. 1 square miles) affected by saline
seeps are as follows:

1941 0. 1 percent

1951 0.4 percent

1956 2. 2 percent

1966 9. 1 percent

1971 19. 4 percent

Of the 19.4 percent, about 15 percent is cultivated dryland, much of
it poorly drained recharge areas that occupy about 5. b percent of
the watershed. If the present alternate crop-fallow farming system
is continued at least 30 to 40 percent of the watershed will probably
be affected by saline seep. This coinpares to less than 0. 1 percent
of the watershed affected by saline conditions under the native sod
system.

Progress since 1969 has been modest at best, but some
awareness has been achieved. In February 1971 the HACA sponsored
the Saline Seep-Fallow Workshop, where data was presented showing
saline seep to be regional in scope and a much more serious environ-
mental problem than previously thought. While MBMG, MSU, and
SCS research continued, additional research was initiated by the ARS
at Sidney, Montana, and Mott, North Dakota, and by the Candian
Department of Agriculture at Lethbridge, Alberta; the HACA made
extensive efforts to secure additional research funds; the 1973 Montana
legislature passed a joint resolution (23) asking the governor to
marshal all state resources and seek emergency aid from the federal
government to halt saline seep; the governor appointed an emergency
saline seep committee to develop a plan for correcting the problem; and
that committee, with the Environmental Quality Council (EQC),
requested technical assistance from the Environmental Protection

Agency (EPA) relating to water quality problems arising from saline
seep.

HYDROGEOLOGICAL SETTING

Much of the definitive hydrogeological work relative to saline
seep has been conducted on the Highwood Bench near Fort Benton.
The details of geological history and mode of seep formation vary from
area to area, but the situation on the bench may serve as a general
model for the entire northern Great Plains region.

The geological history of northern Montana and the bench
included long periods of sedimentation, emplacement of volcanic and
plutonic igneous rocks, regional uplift, erosion, and glaciation.
Throughout most of the Paleozoic and the Mesozoic (600 to 70 million
years ago), thousands of feet of predominatly marine sediments were
deposited in this region. At the end of the Mesozoic (late Cretaceous)
and extending into the early Tertiary (70 to 50 million years ago),
the entire area was uplifted, faulted, and folded, producing the Rocky
Mountains to the west and south, gently tilting the sedimentary rocks
to the northeast, and subjecting the area to erosion. The emplacement
of volcanic and plutonic rocks that form the Highwood and Bearpaw
Mountains also occurred during this time. Continued erosion during
the Tertiary stripped away the uppermost Cretaceous sediments and
exposed the black shale of the Colorado Group over what is now the

Highwood Bench. This same area was dissected and drained by the
ancestral Missouri River, which flowed in a northeasterly direction
to Hudson Bay.

During the Pleistocene (one million to 15,000 years ago),
glaciers covered the entire region north of the Highwood Mountains
two or more times and left a mantle of unconsolidated, poorly sorted
deposits (glacial till) that filled most of the pre-existing valleys and
produced a gently rolling plain. The ice blocked the drainage of the
Missouri River and its tributaries, forcing the streams to change
course and cut new channels. During the last 15,000 years, erosion
established the present-day drainage pattern in northern Montana.

The glacial till and underlying black shale of the Highwood
Bench are geologically important. Drill-hole information and exposures
along the Missouri River show till either absent or up to 70 feet thick.
Two distinct tills, representing two ice advances, are present--the
upper is normally the thicker and is buff to tan, whereas the lower
is generally only a few feet thick (absent in some localities) and is
light to dark gray. A pebble zone or meltwater layer is often found
between the tills. Except for the upper two or three feet- -the leach zone
of the soil profile--the entire till is loaded with salt crystals.

The till is predominatly unsorted clay and silt with well-
rounded pebbles scattered throughout. X-ray analysis of the clay

fraction indicates 80-percent montmorillonite (highly plastic, sodium-
rich, expanding clay), 15-percent illite, and five-percent kaolinite
or chlorite (2). A few sand and gravel lenses were found in some
test holes, but they are normally thin, discontinuous, and small in
area. Numerous vertical joints are believed to enhance the vertical
movement of water through the till. Infiltration studies on poorly
drained upland (recharge) areas indicate down>vard movement of over
five inches of water a day. These high infiltration rates greatly
exceed previous estimates.

The black bentonitic marine shale of the Colorado Group that
underlies the entire Highwood Bench is 950 to 1,850 feet thick. Owing
to erosion and the gentle dip to the northeast, the shale thins to the
southwest toward the Little Belt Mountains. A weathered zone, one
to eight feet thick at the till- shale contact, is commonly saturated
and appears to be the only slightly permeable shale layer. The
unweathered shale beneath is completely dry.

Close correspondence between local precipitation and water-
table fluctuations means that excess water is moving through the soil
to beneath the root zone, through the remainder of the till, and eventually
accunnulating on the bedrock. Most of this movennent occurs in spring,
particularly April, May, and the first part of June. The water table
may rise a few inches to several feet in years with average or above-

10

average precipitation. These highs decline during the rest of the year,
but usually do not reach the previous year's low, reflecting a continual
buildup of excess water. Thus each succeeding wet cycle makes the
saline seep problem worse.

In many areas the "perched" water table has built up to a
point where coulees that were formerly dry most of the year are now
starting to flow year-round. Most of the saline water evaporates
before reaching perennial streams, leaving the salts behind to be
flushed away during spring runoff, but unless the seeps stop growing,
many coulees will soon start to carry highly saline water to all the
region's perennial streams.

Saline seeps are a result of local, not regional, flow systems;
that is, the excess water that produces the seeps is locally derived.
The surface dimension of each wet-saline (discharge) area is directly
related to the size of the adjacent upland (recharge) area. Freshwater
ponds often cover part or all of the recharge area for weeks at a time,
adding large quantities of water to the soil profile and seriously
aggravating the seep problem downslope. The importance of recharge
areas has for the most part been overlooked. Delineation of these areas,
improved drainage where possible, and an intensified cropping system
would mitigate the seep problem. Frequently, the recharge area is
left fallow while attention is focused on the discharge area- -the seep
itself.

11

POTENTIAL REGIONAL PROBLEM

As noted earlier, Montana has already lost over bO, 000 acres
of cropland to saline seep and the area affected is increasing by over
10 percent a year. Geological conditions that favor saline seep--
a variable thickness of glacial till underlain by thick sequences of
black marine 8hale--are similar over vast areas of Montana (12,500
square miles), North and South Dakota (45, 5C0 square miles), and
the three prairie provinces of Canada (70,000 square miles). Saline
seeps are spreading in that entire region and also in farming areas
underlain by the siltstone, sandstone, shale, and coal of the Fort Union
formation (21). Here again, excess water is moving downward and
accumulating on thin impermeable underclays, in this case forcing
the water to move laterally along coal seams until it breaks out at
the surface. The farmed portion of the Fort Union area cover another
100,000 square miles (4,500 in Montana), making a total of 228,000
square nniles (17, 000 in Montana or about 10. 5 million acres) of
potential saline seep in the northern Great Plains (Figure 2). These
plains are the major grain-growing region for North America. The
cropping sequence over the entire region--generally an alternate crop-
fallow system- -is the same as that on the Highwood Bench,

Over 90 percent of eastern Montana's cultivated dryland is in
the Missouri River Basin. Based on discharge records at Fort Benton

12

Saskatchewan

W^W^i^^ AREA OF POTENTIAL SALINE SEEP
00<fiM DEVELOPMENT IN THE NORTHERN
"r^^MMM GREAT PLAINS REGION

Fig.2 Northern Grsat Plains Region, Showing Area of Potential Salme Seep Development.

13

and limited groundwater data, the water table within the glacial till
is rising an average four to ten inches a year and the basin is storing
considerably more water than it did prior to farming. More complete
discharge data from both the Missouri and Yellowstone Rivers reveal
that the Missouri River Basin is storing 4. 3 million acre-feet of water
a year over that being stored by the Yellowstone River Basin, a basin
of much less extensive farming (22). If the annual 4-to- 10-inch water
table rise is projected over all the cultivated farm area of the Missouri
Basin, it accounts for most of the excess storage.

The discharge of the Missouri River, and presumable direct
runoff into the river, was significantly greater from I89I to 1915 than
from 1915 to 1940. Since 1940, discharge has been gradually rising
as excess water began seeping into tributary drainages. The decline
from 1915 to 1940 was undoubtedly accentuated by extended drought.
Even so, groundwater buildup associated with the crop-fallow system
appears to be the most plausible explanation for the reduced discharge.

Saline seep development is most pronounced where the glacial
till is less than 30 feet thick. Excess water appears to be accumulating
over large areas where the till is much thicker, but has not yet reached
the surface. Along with the extensive loss of valuable farmland, wide-
spread deterioration of surface and shallow groundwater resources
seems inevitable as long as factors contributing to this process are
maintained.

14

ECOLCX3ICAL ASPECTS AND IMPLICATIONS

Saline seep is essentially an ecological problem. It involves
all the major components, both biotic and abiotic, of the ecosystem
known broadly as the northern Great Plains. Since 1910 the preponderant
biotic influence upon that ecosystem has been man and his agricultural
systems, only now to be manifest, over half a century later, in the
form of saline seep.

Those who attack the problem need to know how serious the
problem is by inventorying land, water, and biotic resources, and
monitoring any subsequent deterioration. An understanding of complex
ecological relationships responsible for maintaining balance in the
remaining undisturbed portions of the ecosystem is needed in land
management practices.

Environmental Effects

Although saline seep destroys an estimated 8,000 to 25,000
acres of productive Montana land each year, facts are not available
to determine the precise location, extent, and progression of the
problem. To gain such information the Governor's Committee on Saline
Seep recently adopted a standardized form with which to inventory all
agricultural producers in the affected area. Also, state and federal
personnel will try to apply the space-age remote sensing of Earth

15

Resources Observation System (EROS) and Earth Resources Technological
Satellite (ERTS) to delineate the scope of the problem (11) (19). Even
with a more definitive figure of total acreage destroyed, however, the
impact on production of agricultural commodities and the loss in terms
of market value will still be difficult, if not impossible, to ascertain.

Saline seep is certainly responsible in part for increasing
saline pollution of Montana's water (28). The growing unpalatability
of community water supplies at Nashua, Wiota, and Frazer has been
attributed to saline seep (23), and nitrate poisoning of livestock from
salinized farm reservoirs has recently been reported in the Fort Benton
and Denton areas (3). Seeps develop in areas having no alternate source
of fresh water for household, livestock, or wildlife purposes (15).
Siltation from erosion, probably the most important water quality problem
in dryland streams, is likely to increase with loss of vegetative cover
brought on by the seeps (17).

Representative analyses of water and salt samples from the
Highwood Bench and Missouri River, along with recommended standards
for domestic water supplies, are shown in Table 1.

In all surface water, groundwater, and salt sannples collected
on the Highwood Bench, the predonninant dissolved constituents are
sodium, magnesium, sulfate, and nitrate. The samples also contain
unusually high concentrations of trace elements: aluminim, iron.

16

Piraincter

Sulfate (SO4)
\itr.itc(N03)
Chloride (CD
Bicarbonate (HCO3)

Sodium (Na)
Magnesium (Mg)
Calcium (Ca)
Potassium (K)

Strontium (Sr)
Lithium (Li)

Iron (Fe)
Manganese (Mn)
Aluminum {.M)
Copper (Cu)
Lead (Pb)
Zinc (Zn)
Nickel (NO
Cobalt (Co)
Cadmium (Cd)
Clironuum (Cr)
SUver (Ag)

pH

Specific Conductance
(microiKi os)

Total Dissolved Solids

•means "less than."

TABLE 1

Analyses of Salt and Water Samples in the Fort Benton Area.

(All values are in milligrams per liter (in& 1) except as indicated.)

Salt Sample

(microcrams Test Hole
per cram) HC3 (TO)

Ground-
water
Test Hole
BK-2 (701

Test Hole

D21 i72i

Bramlette
Reservoir

lyoy

Surface \^"ater
Bramlette
Reservoir

197;

Recommended
Missouri Drinking

River al \\ater

Fori Beiituii SUiidards

536,000

12,800

10,200

4,000

1 10,000

72,000

8,200

3,340
112-
J,108
5.2-
28.0
22.0
9.6

1.48

26,475

2,262

168

878

4,821

4,607

341

41

33,000
881
255'
288

7,045

4,546

594

6

36,730
918
280
545

5.600

6,295'

446

45'

22.5
2.8

5:1
.87"

8.2-
.12
.78

1.32-
.34
.22-
.11
.12
.08

8:1
1.1

8.^
.70

8:2-
.14
.78
.69
.5i
.25
.12^
.12
.08

7.7"
.99

1.4-

1.1

2^
.12^

1.3
.10
.42:
.38^
.06

.22r

.13

39,690

46,750

50,880

3,600
115

57'
334

7^0

498

215

16

2.0
.28

.14^

.24-

•.10

.02-

.20

.03

.05"

•.05"

.01

•.02-

.02-

8.08 8.35 T.46 8.00
26,700 31.759 31,700 5,860

5,566

5,690
14

96
425

950
908
273

28

2.4-
J38'

.20
.39
•.10
.03
.13
.02:
.03
.10
.01
.02-
.01

T.63

8.110

8.380

55

0

8

163

42.
14
18

.22:
.04^^

.13

.01
1.0

.01
•.02:

.03
•.02:

».02:

•.01
•.02-
♦.OL

8.00

40?

307

250
45

250

.30
.05^

1.0
.05
5.0

.01
.05
.05^

6.0^.5

500

manganese, strontium, lead, copper, zinc, nickel, chromium, ca(iium,
lithium, and silver. Most of these elements are rarely detected in
water samples from other areas. Groundwater samples commonly contain
more than Z5, 000 milligrams per liter (mg/1) total dissolved solids (TDS)
with some exceeding 50,000 mg/1 TDS, which is more saline than sea
water (36,000 mg/1 TDS).

17

High nutrient levels have created eutrophic conditions in
all the small ponds and reservoirs on the Highwood Bench. Almost
all the wells, springs, and reservoirs on the bench, which were once
fresh, are now highly saline. And many of the reservoirs that once
produced trout no longer support a sport fishery. The EPA National
Field Investigations Center, Cincinnati, at the request of the Governor's
Saline Seep Committee and the EQC, will conduct a limnological
reconnaissance of these reservoirs to determine the exact cause or
causes of fish disappearances.

The demise of Highwood Bench reservoirs has been linked to
the acceleration of saline seeps. Three characteristics of saline seep
waters- -TDS, heavy metals, and nutrients- -alone or in combination,
are the suspected causative agents for fish mortalities in these waters.

Levels of heavy metals in at least one reservoir on the
Highwood Bench (Table 1) exceeded recommended water quality standards
for fish and aquatic life (20). TDS were also above recommended levels
for freshwater life, and nitrate was extremely high in the one reservoir
sampled. As noted in Table 1 nitrate is one of the major components
of the salt deposited by seeps on the bench and may be partly responsible
for eutrophication of area reservoirs. Although increased aquatic plant
growth may have depleted oxygen levels and thereby be the single cause

18

of mortalities, the stresses from sublethal oxygen levels may have
made fish more vulnerable to the other toxic agents --heavy metals and
TDS.

Several basic questions must be answered if surface water
quality problems fostered by saline seep are to be dealt with: what
components of seep water are causing the damage; how severe is the
damage and what is the potential for spread; and how may damaged
waters be restored?

The inaplications of seep-caused water pollution are clear.
Montana is a headwater recharge area for downstream states in the
Missouri River Basin, and any degradation of water quality here will
affect downstream uses. Unless saline seep is checked, present water
uses such as drinking, recreation, and fish and wildlife, will be
seriously degraded and water treatment will become more expensive.

The effects of saline seep on wildlife habitat and populations
are even more uncertain. At the fringes of most seeps, salt-tolerant
weeds, mostly Kochia (Kochia scoparia or summer cypress), provide
some cover (and perhaps food) that would not otherwise be available (13).
The seep-affected area is within the range of upland game birds and
migrant waterfowl. In some cases seeps are providing habitat for
these game birds where none existed before (27).

The major concern of the wildlife biologists is that seeps
may eventually destroy or greatly reduce the carrying capacity of the

19

land. One can only speculate on the fate of upland game birds in

Montana's grain belt and of nesting and migrant waterfowl in Montana's

prairie potholes should saline seeps proliferate. Wildlife population

trends in response to the spreading saline problem have not been

established. Perhaps what Aldo Leopold observed 25 years ago can

be expected. He was reflecting upon a jackpine sand farm in Wisconsin

and depleted soils and fallen civilizations in North Africa and the

Middle East:

This. . . display of disorganization in the land seems to
be similar to disease in an animal, except that it never
culminates in complete disorganization or death. The
land recovers, but at some reduced level of complexity,
and with a reduced carrying capacity for people, plants,
and animals (18).

Natural and Agricultural Ecosystems

Research on saline seep in Montana has been insufficient.
Efforts have been restricted to geology and subsurface hydrology, as
described in the first part of this paper, and to soil moisture management
by crop selection and farming practices. These studies should of
course be continued and expanded.

Ultimately, however, the solution to the problem may depend
on understanding complex ecological relationships as they operated,
apparently with some success in forestalling saline seeps, for many
thousand years on the native prairie of the Highwood Bench and similar
areas of the northern plains. Thus it is innportant to compare that

20

native prairie ecosystem with agricultural systems, particularly crop-
fallow, and to understand why the one has succeeded where the other
has failed.

The undisturbed aboriginal prairie ecosystem covering the
glacial till of northeastern Montana represents an accumulated "wisdom"

of about 15,000 years. Since the retreat of the last ice age glacier,
the plant community has been evolving, by trial and error selection

and replacement of species, to the point of optimum environmental
adaptation. The grasses, forbs, and shrubs of the native prairie,
together with the fauna, geology, soils, and hydrology, and such ex-
trinsic factors as precipitation, temperature, solar radiation, and
their seasonality function in a finely tuned dynamic equilibrium that is
only remotely approached in the most diversified of man's agricultural
systems. The ecologic flexibility of the hundreds of native plant
species allows them to form communities adapted to a w^ide array of
environmental situations (including extreme natural fluctuations in
climate, such as very dry, wet, warm, or cold periods). The destiny
of a diverse native plant community is nnore predictable than that of a
homogeneous system such as a field of grain: patchy distribution plus
the inherent resistance of sonrve native species to insects and disease
make the diverse community nauch less susceptible than monoculture to
widespread devastation.

The most innportant characteristics of natural systems in
preventing seeps appear to be efficient water use and restricted

21

vertical percolation. Efficient water use implies a permanently
expanded root system at all depths in the soil profile. Annual grasses
and forbs, like small grain crops, obtain their water only from the
upper soil levels; their root systems are shallow, expanding and
functioning only during the growing season. Perennial grasses and
shrubs, absent from most cropping systems, use water that escapes
from shallow- rooted plants into the subsoil; their root systems are
deeper, permanently expanded, and functional over a longer period.

In nature, big sagebrush (Artemisia tridentata) occupies the
niche of a deep-rooted perennial shrub. A Department of Fish and
Game study in the Winnett area shows that a substantial amount of
moisture was released into the soil during the year sagebrush was treated
with 2,4-D (24). In this study, even perennial grasses could not
grow enough during the season of treatment to consume all the released
moisture.

Precipitation that reaches the ground must either run off,
evaporate, or soak in. Water penetrating the ground surface is
infiltration, whereas water moving through the soil is percolation.

Infiltration studies conducted on fallow and sod (native grass-
land) situations on the Highwood Bench show no appreciable difference
in infiltration rates but greater horizontal water movement with the
sod system. The reason for this greater horizontal movement in sod
is the humus layer at the soil surface. This pourous mulch, usually
over two inches thick, acts as a sponge, or soil moisture storage

22

reservoir, and is able to absorb considerable amounts of precipitation

(10). Although infiltration is aided, the water is distributed horizontally,
allowing it to be used by plants before it has a chance to percolate

below the root zone.

The surface mulch also protects the soil from drying and
consequent structural aberrations. Without this humus cover, clay
soils are subject to alternate wetting and drying, which causes cracks
that allow more rapid and deeper penetration of water (25). As noted
earlier, vertical jointing occurs in the glacial till of the Highwood
Bench. In such situations a surface mulch may be essential to prevent
rapid and excessive percolation of water below the root zone and conse-
quently to prevent the formation of saline seeps.

To apply these and other ecological relationships in land
management and cropping practices will require integrated ecological
research, encompassing geology and hydrology, basic grassland ecology,
and plant and soil science. If the approach is limited to the traditional
realm of agriculture, a practical solution may be no closer than it
is today.

PROSPECTS FOR RETARDATION

Most authorities agree that saline seeps are nearly irreversible;
once the productivity of land is destroyed, reclamation is difficult.
With time, the salts can possibly be leached below the root zone provided
the flow of saline water is cut off. However, the principal objective
is prevention rather than reclamation.

23

As long as the crop-fallow system is practiced on the northern
plains the conditions favoring seeps will continue and the problem
cannot be totally prevented. In certain areas, however, seep flows
can be retarded and perhaps even discontinued.

Serious methods to control saline seep have one objective in
common: remove excess water from the recharge area. The discharge
area, where seeps are manifest, is less important from the control
standpoint. Preventive methods may be grouped into two categories:
farming practices and nonfarming practices.

Farming Practices

To keep excess water from reaching below the root zone in
recharge areas, any vegetation is clearly better than no vegetation
at all (fallow). Stems and leaves intercept moisture and enhance
evaporation. Plants function like pumps in transporting moisture
from the soil up through the roots to the aerial parts, where it can
be transpired. Profitable cereal, seed, or forage crops are a logical
first choice for moisture control purposes.

Currently, soil moisture management through crop selection
and farming methods is probably the only practical means of controlling
saline seep. Reverting to a grassland/grazing economy seems out
of the question in most areas, given today's grain prices and land values.

24

The nonfarming practices listed in the following section do not appear
amenable to widespread application. Because with few exceptions saline
seep is a problem only croplands, an enlightened program of soil
moisture management will depend on the individual producer.

MSU researchers are examining several approaches to seep
control in studies on the Highwood Bench (4); their preliminary findings
are available to farmers in a recent bulletin from the MCES (5).

An initial alternative is to crop small grains every year
instead of every other year, but this method of seep control does not
appear to be feasible. Since winter and spring w^heat use soil moisture
to a depth of only four to seven feet, and root systems may not be
established at snowmelt or when rains arrive, water may still move
beyond the root zone in wet years. Only a few of the minor seeps
have disappeared from the Highwood Bench after two dry years in
combination with annual cropping (5). Also, harvest during the second
or subsequent years may be too meager to pay farming costs, except
in areas receiving adequate annual precipitation.

Deep snow accumulation may be responsible for particular
saline seeps, but a certain amount of snow accumulation is needed for
successful annual cropping. Standing stubble and intermittent rows of
perennial grasses, which can hold snow in place and reduce drifts,
are being studied by MSU and ARS as means of controlling the amount
of water entering the soil in recharge areas.

25

Dryland alfalfa and intermediate and tall wheatgrasses are
better prospects than small grains for drying out soil and subsoil on
recharge areas (5). Sweetclover, sainfoin, vetch, corn, millet, and
safflower were also tested by the MSU team, but these plants used
less soil moisture than wheatgrass or alfalfa. Although effective,
widespread conversion to these crops will raise serious economic,
ecologic, and practical questions. For example, can farmers adapt
mechanization to changing crops and still be able to operate at a
profit? Can a market for forage or seed crops be established and
maintained in a region now largely devoted to cereal crops? What will
be the long-term environmental consequences of such crop conversions?

According to the MSU studies, Kochia is effective at reducing
soil water; it grows primarily in saline soils on discharge areas;
and it may produce over five tons of forage an acre (4), Kochia also
makes excellent hay; "cattle eat it just like alfalfa (1)" Besides being
palatable, it is nutritious (12).

Although deep-rooted and a vigorous water user, Kochia left
standing over winter will trap snow, which will contribute to the seep
the following spring. No evidence shows, however, that such moisture
accumulation in the form of snow will exceed or even approach the amount
used by the plant during the growing season. Furthermore, snow accumu-
lation on discharge areas (where Kochia grows) is not as critical in
perpetuating seeps as accumulation on recharge areas. Kochia is

26

apparently well adapted to growing in seeps where agricultural plants

have failed, and any proposals for control of this plant and replacement

by others should be seriously examined. Fertilizer applications are

known to enhance plant growth in some situations and thereby aid in

soil water reduction. Only as much fertilizer as the plants can use should

be applied; otherwise excess nutrients might contaminate surface

and ground waters.

Farmers need to recognize that successful cropping in seep
areas must include soil moisture and water table management. A
simple soil auger should become standard equipment to help farmers
decide whether to plant and what to plant depending on soil moisture
content and depth to groundwater. Farmers will need to consider the
penetration and character of root systems as well as above-ground
plant production; they may need to diversity- -to call on any one of a
number of crops depending on moisture use and needs. Water tables
should not be allowed to rise any further, yet adequate soil moisture
in the root zone is a prerequisite to profitable cropping. Some way,
a moisture balance must be maintained, neither too little nor too much
can be tolerated.

For convenience and economy, farming has traditionally been
practiced on geometric land patterns, usually rectangles or squares.
Within the last half-century the average size of these units has greatly

27

increased, mainly because of large, mechanized farm implements.
However, the diverse characteristics of soil, subsoil, substrata,
and surface and subsurface hydrology do not conform to these regular
patterns. On larger fields especially, these land features,, many of
which determine the potential for seep development, are not consistent.
Applications for controlling seep may be necessary and effective in
one part of a field, yet unnecessary and ineffective or even counter-
productive in another. For example, a field might cover both a
recharge area and a discharge area with varying soil moisture content
and water table levels throughout; a deep-rooted perennial would be
effective where the water table is deep and surface moisture deficient,
but annual cropping to small grains may be more productive and equally
as effective where surface moisture is adequate.

In short, farmers may not be able to continue imposing
conventional field geometry and still hope to solve the problem of
saline seep. They may need instead to adapt more closely to the varied
capabilities and constraints of the land, which in some areas may mean
smaller fields, fields of irregular shape, both of these, or possibly no
farming at all. They may also be unable to continue present monocultural
cropping practices. Farmers, in certain situations, should be willing
and able to crop not only cereal grains but also grasses, legumes, or
whatever else may be suitable.

28

Nonfarming Practices

Nonfarming methods control both the flow of fresh water into
the recharge area and the flow of saline water from the discharge area.
They include underground drainage, ponding, land grading, and phrea-
tophytes. (A phreatophyte is a plant capable of drawing its supply of
nnoisture from the groundwater reservoir or from the capillary fringe
above it. )

Land grading is probably the most feasible and effective
alternative. This involves contouring the land surface in recharge
areas to enhance runoff and eliminate short-term ponding on fallow
fields, thereby reducing the water contributing to seeps. Runoff could
be directed along grassed drainageways to reduce erosion potential.

The conventional method of lowering water tables is artificial
drainage. But the impermeability and thickness of the till (it averages
about 25 feet), and the problem of what to do with the saline water,
make artificial drainage of the discharge areas infeasible. Most
affected areas would require a very extensive and expensive network
of tiles (16).

In any event, the question remains--what is to become of
the excess saline water now flowing freely from the ground? Contamina-
tion of fresh surface waters is clearly a problem, and any purposeful
discharge through drainage and/or diversion of saline waters would

29

certainly conflict with state and federal nondegradation policies.

One method of saline water control is to collect saline dis-
charges in sealed ponds and to allow the water to evaporate, leaving
the salts behind. This method would disturb a considerable amount of
land and would probably not be economically feasible (16).

Another method of managing seep water in discharge areas
is to establish stands of salt-tolerant phreatophytes. One candidate is
five-stamen tamarisk (Tamarix pentandra), a decidious tree native to
Eurasia whose root system sometimes extends 90 feet or more down
to the water table. This species has spread with explosive speed
through the drainage systems of the Southwest. Other nonspreading
Tamarix species may be more desirable.

Nevertheless, native plants should be considered before
contemplating introductions. More likely candidates from area flora
include saltgrass (Distichlis stricta), picklewood (Salicornia rubra),
and species of Suaeda or seep weed. Kochia and foxtail barley (Hor-
deumjubatum) naturally take over seep areas but occupy only the dry
fringes.

These and other steps may be necessary to prevent the progressive
depletion of the soil resource base of northeastern Montana and other
glaciated lands of the northern Great Plains. In the words of State
Senator George Darrow, saline seep is

30

. . . not an isolated local problem, it is a systemic problem
. . . The overall dimensions of the saline seep problem involve
nothing less than the future of Montana's agricultural economy.
We now understand that that future is in jeopardy. Our
response will determine that future (9).

TENTATIVE RESEARCH CONCLUSIONS

1. Although water contributing to saline seeps is locally
derived, the problem is regional and systemic, potentially encompas-
sing a major portion of the northern Great Plains in both the United
States and Canada.

2. Natural grassland systems are more effective than agri-
cultural systems in forestalling saline seep development.

3. Saline seeps are clearly caused by the present crop-fallow
system of farming superimposed on the hydrologic and geologic condi-
tions of the northern Great Plains.

4. Soil and water pollution are the two most severe environ-
mental impacts of saline seep; little is known about its impact on wildlife
populations.

5. The true extent of losses from saline seep, in terms of
productive land surface and market value of agricultural commodities
is unknown,

6. Reclamation proposals are only stopgap solutions; the

only real hope lies with individual producers and an enlightened program
of soil moisture management based on sound ecological principles.

31

7. The majority of the excess water moving downward through
the glacial till and accumulating on the impermeable shale comes during
the spring months of the year--March, April, May, and June.

b. On fallow areas, a water-table rise of one to five feet
can be expected during years with average or above average spring
precipitation. These water table highs gradually decline during the
rest of the year, but normally do not reach the previous year's low
indicating a continual build-up of excess water over the years. As a
result, each succeeding wet cycle makes the saline-seep problem worse.

9. The size of each wet-saline area (discharge area) is related
directly to the size of the adjacent upland recharge area. Every effort
should be made to delineate the major recharge areas to make sure that
the cropping system is intensified in these areas. Frequently, all the
attention is given to the seep (discharge) area and the upland (recharge)
area is left fallow.

10. In many areas the "perched" water table has built up to a
point where coulees which were formerly dry most of the year are now
starting to flow year-round. At the present time most of the saline
water is evaporated before reaching the perennial streams leaving the
salts behind to be flushed away during spring runoff. Unless the growth
and development of saline seeps are stopped soon many coulees will
start to flow appreciable quantities of highly saline water to all perennial

32

streams throughout the region with the majority of the water coming
during the low-flow season when it could rapidly impair the quality of
the entire stream. Because Montana is a headwater state for the Missouri
and Yellowstone River Basins, the potential widespread deterioration
of water quality is of national interest and concern.

11. In all water and salt samples collected on the Highwood Bench
area, the predominant dissolved constituents were sodium (Na),
magnesium (Mg), sulfate (SO.) , and nitrate (NO_). The samples
analyzed so far also contain unusually high concentrations of trace
metals, namely aluminum, iron, manganese, strontium, lead, copper,
zinc, nickel, chromium, molybdenum, selenium, and vanadium. The
majority of these metals are rarely ever detected in water samples.
Groundwater samples commonly contain more than Z5, 000 milligrams
per liter (mg/1) total dissolved solids. High nutrient levels (nitrates

and phosphates) have created eutrophic conditions in all the small ponds
and reservoirs in the area. Practically all the springs and reservoirs
on the Highwood Bench which were once fresh water are now highly
saline. This relatively rapid deterioration of all potable water supplies
in this area should serve as a warning to what may happen to the water-
resources of the entire region if the saline-seep problem is ignored.

12. All available hydrogeological data indicate that the formation
and development of saline seeps are a result of local, not regional, flow
systems.

33

13. Infiltration studies on high, poorly drained, recharge
areas indicate that over five inches of water per day can move downward
through the glacial till. These high infiltration rates greatly exceed
previous estimates.

14. Saline- seep development is not just limited to high precipi-
tation areas. During the past two years large outbreaks of saline seeps
have been observed in areas where average annual precipitation is less
than 12 inches (Loma, Power-Dutton, and Columbus-Rapelje areas).

15. At the present time saline- seep development is particularly
pronounced in areas where the glacial till is relatively thin (zero to 30
feet thick). Excess water is undoubtedly accumulating over large areas
where the glacial till is much thicker, but as yet has not expressed
itself at the surface.

16. According to a survey conducted by the United States Soil
Conservation Service in 1971, more than 80,000 acres of non-irrigaged
cropland in Montana had been lost to saline seeps. Serious outbreaks
of saline seeps have now appeared in most of northcentral and north-
eastern Montana. At the present time, it is estimated that an additional
area of 100, 000 to 150, 000 acres of cropland has been lost, but no
recent survey has been conducted to prove or disprove this estimate.
Possibly such a survey should be conducted soon. Also, if the acreage of
saline farm, recreation, and stock ponds, as well as badly eroded

34

coulees and "seeped" drainageways were included, the affected area
would be much greater.

17. Geological conditions, that is, a variable thickness of
glacial till underlain by thick sequences of black marine shale (Colorado
and Bearpaw Formations), are similar over vast areas of Montana
(12, 500 square miles), North Dakota and South Dakota (45, 500 square
miles) and the three prairie provinces of Canada (70,000 square miles).
In addition to the above-mentioned region, saline seeps are also spreading
in areas underlain by siltstone, sandstone, shale, and coal (Fort Union
Formation). Here again excess water is moving downward and accumu-
lating on thin impermeable shale beds forcing the water to move laterally
along coal seams until it breaks out at the surface. This area covers
an additional 100,000 square miles making a total of 228,000 square
miles of potential saline- seep development in the northern Great Plains
region of the United States and Canada. This is the major grain-growing
region for both countries. The cropping sequence over this entire
region--generally an alternate crop-fallow system--is the same one
being used on the Highwood Bench, northcentral Montana.

35

RECOMMENDATIONS

1. Initiate an extensive, coordinated research program dealing
with all aspects of the saline seep problem. Critical research needs
include accurate information on:

A. Total acreage affected.

B. Annual loss of crops and livestock in terms of market
value.

C. Extent of seep-caused water quality problems and cost
of restoring affected waters to beneficial use.

D. And, impacts on fish and wildlife resources and losses
to the associate recreation industry.

2. Identify major recharge areas and where feasible improve
the runoff efficiency on fallow fields to avoid ponding.

3. Intensify cropping practices over the entire northern plains
region, particularly in recharge areas and during years with average
or above average spring precipitation.

4. Rotate perennial grasses and deep-rooted legumes into the
cropping program. Available data show that alfalfa can use soil moisture
to a depth of 25 feet once it gets established.

5. Determine why the native plant cover, working together
with the hydrologic and soils regime, has been able to prevent saline
seeps, and apply this knowledge in farming practice.

36

FUTURE PLANS

The widespread occurrence and rapid growth of saline seeps
have now been recognized as one of the most serious conservation
problems in the Northern Great Plains. The funds received from the
Office of Water Research and Technology for this project were instru-
nnental in providing "seed" money to initiate an active research program
to study this problem.

Throughout the project there has been very close cooperation
between the Montana Bureau of Mines and Geology, Montana State
University, Montana Agricultural Experiment Station, Montana Exten-
sion Service, Montana Environmental Quality Council, United States
Agricultural Research Service, United States Soil Conservation Service,
United States Geological Survey, United States Environmental Protection
Agency, and local farming organizations. The principal investigator
has been responsible for the hydrogeological aspects of the problem.
The results and information gathered during the project have been used
by all the other organizations.

A new project partially supported by the Office of Water
Research and Technology funds has been initiated to examine the
regional development of saline seeps. This will be a cooperative
venture with the aforementioned organizations and much of the data
gathered for this study will be used in these future studies.

37

LITERATURE CITED

1. Anderson, R. (farmer and chairman. Governor's Saline Seep Committee,

Fort Benton). 19'73. Telephone conversation of November Z.

2. Berg, R, B. (economic geologist. Geological Division, Montana Bureau

of Mines and Geology, Butte). 1973. Personal communication.

3. Brown, P. L. (research soil scientist. Agriculture Research Service,

Fort Benton). 1973. Telephone conversation of November 2.

4. Brown, P. L. and H. Ferguson 1973. Crop management in Montana

for control of dryland salinity. In Proceedings of the Alberta Dryland
Salinity Workshop, Alberta Department of Agriculture, Edmonton.

5. Brown, P. L. and H. Ferguson. 1973. Saline seep. Preliminary:

possible control practices. Folder 148, Cooperative Extension
Service Montana State University, Bozeman. June.

6. Clark, C. O. 1971. The mechanics of saline-seep development on non-

irrigated cropland. In Proceedings of Saline Seep Fallow Workshop,
Great Falls.

7. Clark, C. O. (soil scientist, USDA, Soil Conservation Service, Great

Falls). 1973. Personal communication.

8. Coues, E. (ed. ) 1965. History of the expeditionunder the command of

Lewis and Clark, Vol. I. Dover Publications, New York.

9. Darrow, G. (member, Montana Seante, Billings). 1973. Notes on the

first emergency meeting on saline seep. Governor's office, Helena,
April 25.

10. Donahue, J. J. Jr. and J. M. Ashley. 1973. Impacts of induced rainfall

on the Great Plains of Montana. Section 7- -Surface Hydrology.
Research Report 42, Montana Agricultural Experiment Station, Montana
State University, Bozeman, July, 1973.

11. Dundas, R. T. Jr. (director. Information Systems Division, Department

of Intergovernmental Relations, Helena). 1973. Telephone conversa-
tion of September 28.

3b

12. Erickson, E. L, 1947. Forage from Kochia. South Dakota Agricultural

Experiment Station Bulletin 384.

13. Feist, F. (wildlife biologist, Montana Fish and Game Department, Great

Falls). 1973. Telephone conversation of April 20.

14. Ferguson, H., P. L. Brown and M. R. Miller, 1972. Saline seeps on

non-irrigated lands of the northern plains. In Proceedings on control
of agriculture related pollution in the Great Plains, Lincoln,
Nebraska. Great Plains Agricultural Council Publication No. 60.

15. Ferguson, H. (professor, Plant and Soil Science Department, Montana

State University, Bozeman). 1973. Memo to Governor's Emergency
Committee, September 7.

16. Gemmell, B. B. (state conservation engineer, USDA, Soil Conservation

Service, Bozeman). 1973. Telephone conversation of September 13.

17. Johnson, R. (fish biologist, Montana Fish and Game Department, Great

Falls). 1973. Telephone conversation of April 20.

18. Leopold, A. 1969. A Sand County Almanac, Oxford University Press, N. Y.

19. May, G. (NASA, Goddard Space Flight Center, Greenbelt, Md. ). 1973.

Telephone conversation of September 24.

20. McKee, J. E. and H. W. Wolf (eds. ). 1963. Water quality criteria.

State Water Quality Control Board, Sacramento, California.

21. Miller, M. R. 1971. Hydrogeology of saline-seep spots in dryland

farm areas--a preliminary evaluation. In Proceedings of Saline Seep -
Fallow Workshop, Great Falls.

22. Miller, M. R. and E. W. Bond. 1973. Impacts of induced rainfall on

the Great Plains of Montana. Section 8- -Ground water hydrology,
Montana Agricultural Experiment Station, Montana State University,
Bozeman, July. Research Report 42,

23. Montana Legislature. 1973. Senate Joint Resolution 33.

24. Pyrah, D. B. , R. O. Wallestad, and H. E. Jorgensen, 1973. Ecological

effects of sagebrush control. Job progress report, Research Project
No. W-105-R-7, 8. State of Montana, Department of Fish and
Game, April 20.

39

25. Ryerson, D. E. (professor of Range Science, Department of Animal
and Range Sciences, Montana State University, Bozeman). 1973.
Telephone conversation of September 6,

Z6. Thacker, W. 1973. Montana's dryland salinity control program. In
Proceedings of the Alberta Dryland Salinity Workshop, Alberta
Department of Agriculture, Edmonton.

27. Trueblood, R. (wildlife biologist, Montana Fish and Game Department,

Glasgow). 1973. Telephone conversation of April 20.

28. U. S. D. A. 1971. Montana situation statennent. USDA State Committee

for Rural Development. December 31.

29. Warden, R. W. 1954. Why that north slope alkali? Montana Farmer

Stockman. September 1,

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