Riparian Landscapes - Mountains and Plains: The Ecology of Wyoming Landscapes - page 60

by erosion caused by wagon trains. Yet even the best
beaver construction sometimes fails, especially with
exceptionally high spring floods. Beaver populations
could have been diminished for other reasons as well,
including disease and periods of drought. Whatever the
cause, the evidence suggests that, though gullies were
present prior to euroAmericans, they are probably more
common now (see chapter 2). 26

limbs and give them every night as the buffaloe [ sic ]
have entirely destroyed the grass throughout this part
of the country.” 28
However, the explorers did not provide information
on the amount of time the bison spent in a particular
area. Without fences, bison would have wandered at
will, possibly grazing an area heavily but not returning
to the same place for a year or more. Also, the upland for-
age then, away from the rivers, might have been attrac-
tive to bison more than to livestock. today water tanks
and salt blocks are used to draw cattle to the upland, at
least for a portion of the year. But in some areas it seems
as though the only solution to conserving the riparian
habitat and streamwater quality is additional fencing or
labor-intensive herding.
one of the undesirable consequences of heavy graz-
ing along creeks and rivers is bank erosion, which leads
to a decline in bank storage, water quality, and habi-
tat. 29 Such erosion can occur at any elevation, revers-
ing a natural tendency, namely, sedimentation near the
banks where the flow is slower and a gradual narrowing
of the channel as sediments are stabilized by plants. the
deeper, narrower streams often have overhanging banks
that provide excellent fish cover (fig. 4.15). Hooved
animals, however, whether livestock or big game, can
destroy the banks, thereby reducing water storage capac-
ity, widening stream channels, and increasing water
temperatures. 30 consequently, fish habitat is degraded.
Several studies have documented these trends and the
fact that better livestock control improves fish produc-
tion in small streams. 31
Poor livestock management is not the only potential
cause of stream degradation. Bank erosion often occurs
with road construction and other developments, and
nutrients can enter the water by seepage from feedlots,
fertilized cropland, and inadequate sewage treatment
systems. Such factors may be as serious for lakes and
reservoirs as for the streams. A case in point is Flam-
ing Gorge Reservoir near the Wyoming-Utah border,
where the upper part of the reservoir has algal blooms
that can interfere with recreational activities—possibly
because of nutrient additions to the Green River that
cause undesirable changes to the aquatic ecosystem.
in the Greater Yellowstone Area, various investiga-
tors have concluded that willow and cottonwood were
once more common when concentrations of elk on win-

Livestock, Reservoirs, and Irrigation

Riparian habitats have long been important to people
living in the semi-arid West. Beaver trapping and placer
mining for gold took place along creeks and rivers, and
abundant forage and irrigation water facilitated agri-
cultural development. Most farms, towns, and cities
are located nearby, partly because of the availability
of water but also because of the aesthetic appeal of
riparian zones. Floods continued to occur, often caus-
ing great damage to riverside settlements, but usually
the accepted solution for the flood problem was dam
construction or channelization. Floodplain ameni-
ties kept people from moving to higher ground. Dams
not only prevented spring floods, they also provided
opportunities for waterpower, irrigated agriculture,
and recreation.
today, more people than ever want access to the
resources provided by riparian landscapes. the result
is high land prices and increased concern about ripar-
ian management. three topics are especially relevant
in this regard: livestock grazing, reservoir construction
and management, and the effects of different irrigation
systems.

Livestock

Domestic livestock concentrate where water, food,
and shade are in close proximity, sometimes leading
to excessive grazing. Large numbers of bison could
have had the same effect on streams as cattle or sheep.
indeed, travelers in the early 1800s observed thou-
sands of bison grazing along rivers. 27 one of the earliest
explorers, osborne Russell, wrote about southern Mon-
tana in 1835: “the bottoms along these rivers are heav-
ily timbered with sweet cottonwood and our horses and
mules are very fond of the bark which we strip from the