Physical History of the Platte River in Nebraska

• Description: related to the Platte River Endangered Species Partnership ‎(aka Platte River Recovery Implementation Program or PRRIP)‎,
• State: NE
• State: CO
• State: WY
• Basin: South Platte
• Water Division: 1
• Date: 8/1/2000
• Author: Simon & Associates, Inc.
• Title: Physical History of the Platte River in Nebraska: Focusing Upon Flow, Sediment Transport, Geomorphology, and Vegetation
• Water Supply Pro - Doc Type: Report/Study

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Significant changes in groundwater hydrology have occurred along the Central Platte
River due to a number of factors. Large numbers of wells have been developed,
primarily to irrigate land. The consumptive use of water pumped from wells tends to
draw groundwater levels down. The development of irrigation canals and laterals, as
well as lakes and reservoirs, fed by surface water diverted from the river generally tends
to increase groundwater levels. Changes in water surface elevation along the river due to
channel bed elevation changes caused by aggradation or degradation would be expected
to affect adjacent groundwater levels. Groundwater data were obtained from a variety of
sources (the NNRIS Data Bank of the Nebraska Natural Resources Commission in
cooperation with the USGS, USGS Water Supply Papers, CNPP &ID, Twin Platte Natural
Resources District, and Conservation and Survey Division of the University of Nebraska)
by Simons & Associates (1990b) to evaluate the causes of change in groundwater levels.
Adjacent to the river, the water table has remained relatively stable with no significant
trends over time as shown in Figure 2.18, typical of well data near the river.
2.4 Sediment Supply and Transport History
Descriptions of the Platte River refer to its muddy or turbid nature. Eschner et al. (1983)
present several references regarding this characteristic.
The water of the Platte River commonly was referred to as muddy or
turbid. The "turbid waters of the Platte " were noted by the Long
Expedition (James, 1823). McKinstry (1975), although calling the Platte
a river of sand, stated that it was "nearly as muddy" as the Missouri.
Taylor (Williams, 1969) wrote that the river was at various points, "swift
and muddy, " "muddy and turbulent, " and "broad, swift and muddy. "
Kelly (1851) described the river as turbid. Ebey (Baydo, 1971) stated of
the Platte: "The water is always muddy and turbid * * *. "
The general consensus of these accounts is that the Platte River, in its pre - development
state, transported a significant quantity or concentration of sediment. The history of
sediment supply and transport cannot be quantified to the degree that flow can. This is
due to the fact that no known sediment transport data were collected until after almost all
of the current level of water resources development had been completed.
2.4.1 Suspended Load
The earliest quantification of sediment transport occurred in the form of suspended
sediment samples collected in the late 1940's. Appendix A documents the availability of
suspended sediment data in the Platte River Basin. These data consisted of suspended
sediment samples at a frequency of periodic spot readings (on the order of once a month)
to daily readings for a few years at a time.
2.4.2 Bed - material load and grain size distribution
Some bedload transport data were collected, primarily in the 1980's. These data
generally consisted of some spot measurements at a variety of locations as documented in
Appendix A. Along with the quantity of bedload transport, some samples of the grain
size distribution of bedload were collected and analyzed.
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