USGS Science⌕ Search

Geology topics

C.H. Scott

Publications and source records attributed to C.H. Scott.

5 recordsLinked to original sources
USGS1969

Stage-discharge characteristics of a Weir in a sand-channel stream

A unique relation between water-surface elevation and water discharge usually does not exist for sand-channel streams. The relation is affected by changes in bed roughness and changes in bed elevation because of scour and fill. An artificial control on a sand-channel stream must control both the resistance to flow and the bed elevation in order to stabilize the relation between water-surface elevation and water discharge. The weir (control structure) in the Rio Grande conveyance channel near Bernardo, N. Mex., was designed on the basis of a model study and field data (Harris and Richardson, 1964). About 72 percent of the measurements used to define the base relation between water-surface elevation and water discharge falls within plus or minus 5 percent of the mean relation for the prototype. The stage-discharge relation is not affected by backwater for values of submergence less than 90 percent. There is no consistent relation between the ratio of measured discharge to rated discharge and submergence for values of submergence greater than 90 percent. The control does not restrict the channel capacity to less than the stated design capacity of 2,000 cubic feet per second. When the control is drowned out, or ineffective, the relation of water-surface elevation to water discharge is virtually the same as that prior to construction of the control for discharges greater than 1,500 cubic feet per second. When the control is not drowned out--that is, free-fall conditions exist--the water-surface elevation for a discharge of 2,000 cubic feet per second is greater than the minimum elevation, but is less than the maximum elevation that occurred at that discharge prior to construction. The model study was only partially successful in predicting the operating characteristics of the prototype. Some of the differences between prototype operation and model predictions may exist because the prototype was not built exactly as recommended on the basis of the model study. In general, the prototype has operated somewhat better than the model predicted.

Water Supply Paper↗
USGS1968

Chemical quality of surface waters in Devils Lake basin North Dakota, 1952-60

Above-normal precipitation in 1954, 1956, and 1957 caused the water surface of Devils Lake to rise to an altitude of 1,419.3 feet, its highest in 40 years. Nearly all the water entering the lake flowed through Big Coulee, and about three-fourths of that inflow was at rates greater than 100 cubic feet per second. At these rates, the inflow contained less than 600 ppm (parts per million) dissolved solids and was of the calcium bicarbonate type. Because the inflow was more dilute than the lake water, the dissolved solids in the lake decreased from 8,680 ppm in 1952 to about 6,000 ppm in 1956 and 1957. Subsequently, however, they increased to slightly more than 8,000 ppm and averaged 6,800 ppm for the 1954-60 period. Sodium and sulfate were the principal dissolved constituents in the lake water. Although the concentration of dissolved solids varied significantly from time to time, the relative proportions of the chief constituents remained nearly the same. Water flowed from Devils Lake to Mission Bay in 1956,1957, and 1958, and some flowed from Mission Bay into East Bay. However, no water moved between East Devils Lake, western Stump Lake, and eastern Stump Lake during 1952-60; these lakes received only local runoff, and the variations in their water volume caused only minor variations in dissolved solids. For the periods sampled, concentrations averaged 60,700 ppm for East Devils Lake, 23,100 ppm for western Stump Lake, and 127,000 ppm for eastern Stump Lake. Sodium and sulfate were the chief dissolved constituents in all the lakes of the Devils Lake chain. Water in eastern Stump Lake was saturated with sodium sulfate and precipitated large quantities of granular, hydrated sodium sulfate crystals on the lakebed and shore in fall and winter. A discontinuous layer of consolidated sodium sulfate crystals formed a significant part of the bed throughout the year. Measured concentrations! of zinc, iron, manganese, fluoride, arsenic, boron, copper, and lead were not high enough to harm fish. Data on alpha and beta particle activities in Devils Lake were insufficient to determine if present activities are less than, equal to, or more than activities before nuclear tests began. Miscellaneous surface waters not in the Devils Lake chain contained dissolved solids that ranged from 239 to 61,200 ppm. The lakes that spill infrequently and have little or no ground-water inflow and outflow generally contain high concentrations of dissolved solids. Salt balance computations for Devils Lake for 1952-60 indicate that a net of as much as 89,000 tons of salts was removed from the bed by the water in some years and as much as 35,000 tons was added to the bed in other years. For the 9-year period, the tons removed exceeded the tons added; the net removed averaged 2.7 tons per acre per year. Pickup of these salts from the bed increased the dissolved solids in the lake water an average of 193 ppni per year. Between 1952 and 1960, 201,000 tons of salt was added to the bed of East Devils Lake, 15,100 tons to the bed of western Stump Lake, and 421,000 tons to the bed of eastern Stump Lake. Laboratory examination of shore and bed material indicated that the shore contained less weight of salt per unit weight of dry, inorganic material than the bed. Calcium and bicarbonate were the chief constituents dissolved from bed material of Devils Lake, whereas sodium and sulfate were the chief constituents dissolved from bed material of East Bay, East Devils Lake, and eastern and western Stump Lakes. Generally, calcium and bicarbonate were the chief constitutents dissolved from shore material of all these lakes. Evidence indicates that not more than 20 percent of the salt that "disappeared" from the water of Devils Lake west of State Route 20 as the lake altitudes decreased years ago will redissolve if the lake altitude is restored.

North Dakota↗