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Hydrologic Data for Urban Studies in the Austin, Texas Metropolitan Area, 1980
This report includes drainage basin maps and information from a specific storm (May 12, 1980) for the 23rd and 38th street Waller Creek locations.Waller Creek Working Grou
Modifications to Gate-Flume Structures on the Weber Davis Canal
The turnout structures under study divert flows from the Weber-Davis Canal near Clearfield, Utah. A portion of the canal in this area was realigned as a result of the construction of the Interstate Highway System. The twin turnout structures, used to divert water to the West Branch Irrigation Company and West Layton Irrigation Company, were constructed in conjunction with the realignment of the concrete -lined canal.
A three-dimensional drawing of the twin turnout structures is shown in Fig. 1. Water is diverted from the canal by passing under the discharge diverted through each of the structures is approximately 35 cfs (cubic feet per second, or second-feet). To properly allocate and assess the quantity of flow delivered to each of the irrigation companies, Parshall flumes having a throat width of four feet and a depth of four feet were placed inside each structure. After passing through the Parshall flumes, the water is conveyed by twin corrugated metal arch pipelines, located under the newly constructed freeway, to existing irrigation distribution systems which serve lands west of the highway. A portion of the twin turnout structures are covered with concrete (Fig. 3) to accommodate the service road located on the west side of the canal.
One of the difficulties encountered in the design of the structures was the space available between the canal and the cut bank on the freeway right-of-way. This space limitation resulted in the entrance of the four-foot Parshall flume being located less than nine feet away from the diversion gate. The situation was further aggravated by placing the lip of the gate opening two feet lower than the bottom of the canal. The net result was a high velocity jet passing under the gate with maximum velocities reaching 15 feet per second. The high velocity jet resulted in considerable turbulence and wave action within the structure. The instability of the flow created concern regarding the reliability of the standard calibration for Parshall flumes in predicting the actual flow being diverted to each of the two irrigation companies. In an effort to reduce the height of waves, a metal stilling float was placed in each structure (Fig. 4). The floats did not materially improve the flow conditions
Evaluation of free and submerged flow data for large parshall flumes
Because the accurate measurement of water plays such an important part in water management, such structures as weirs, orifices, calibrated gates f and flumes have been developed. These structures provide the means for reasonable measurement of the smaller flows (1: .. 100 cfs), but for the large flows (100-3,000 cfs) the current meter, large Parshall flume, and various other flumes are commonly used. Where a permanent structure is required, the most widely accepted and utilized method for measurement of large flows is probably the Parshall flume. The purpose of this report has been to collect the existing flow data for large Parshall flumes having throat widths of 10, 12, 15, 20, 25, ,30, 40, and 50, feet, and evaluate from the data certain free flow and submerged flow relationships. The free flow relationships of large Parshall flumes as listed by R . L. Parshall (1932) are verifieq. from the data. The study reported herein was further made to illustrate that the analysis of submergence developed at Utah State University for smaller Parshall flumes (Skogerboe, Hyatt. Johnson, and England, 1965) is also applicable to large Parshall flumes
Rectangular Cutthroat Flow Measuring Flumes
Introduction: Procedures and methods for more accurate measurement and improved management of water are continually being sought to make better use of our water resources. Of all the devices and structures developed for measuring water, measuring flumes are among the most widely accepted and used. The most common measuring flume is the Parshall flume developed by Ralph Parshall at Colorado State University. Common to most flumes is the basic geometry consisting of a converging inlet section, a throat, and a diverging outlet section. Occasionally, the diverging outlet section is removed under free flow conditions, and the water is allowed to jet directly from the throat section into the downstream channel. This is not always permissible, however, in unlined channels because of possible erosion problems. In flat gradient channels, a flume may be installed to operate under conditions of submerged flow rather then free flow in order to (1) reduce energy losses, and (2) allow placement of the flume on the channel bed to minimize the increase in water surface elevation upstream from the flume. The purpose of the research effort reported herein was to develop a flume which would operate satisfactorily under both free flow and submerged flow conditions
Analysis of Submergence in Flow Measuring Flumes
Submerged flow exists in a measuring flume when a change in flow depth downstream from the flume causes a change in flow depth upstream for any particular constant value of discharge. When a change in tailwater depth does not affect the upstream depth, free flow exists. To evaluate the discharge under free-flow conditions, it is necessary to measure only a flow depth upstream from the contracted section (throat) of the flume, whereas two flow depths must be measured to evaluate the discharge under submerged-flow conditions. The two flow depths normally measured when submerged flow exists consist of the same upstream depth used for free flow and a depth measured in the throat, although this need not be the case as will be shown later. Most of the earlier investigations regarding measuring flumes have emphasized the development of free-flow calibrations or ratings for various flume geometries. Notable free flow investigations have been made by V. M. Cone, Parshall, Engel, Khafagi, Robinson and Chamberlain, and Ackers and Harrison, to mention a few. Various methods of analyzing submerged flow have been presented by Parshall, Khafagi, Villemonte and Gunaji, Robinson and Chamberlain, and Robinson. Parameters describing submergence in flow-measuring flumes will be developed from dimensional analysis. A combination of empiricism and dimensional analysis will be used to develop a submerged flow discharge equation. The resulting discharge equation will be compared with the theoretical submerged-flow equation developed from momentum relationships. A rectangular flat-bottomed flow measuring flume was used to generate data necessary for establishing the parameters describing submerged flow. The form of the discharge equations describing submerged flow in a rectangular flume has been verified for a trapezoidal flat-bottomed flume, a rectangular flat-bottomed flume, and a Parshall flume
Subcritical Flow Over Highway Embankments
Introduction: At Utah State University, considerable effort has been devoted to the analysis of submerged flow at open channel constrictions. A method of analyzing subcritical (submerged) flow has been developed for flumes. Because of previous findings, it was felt that this method of analyzing submerged flow could be applied to highway embankments. A highway embankment, when overtopped by flood waters, is a form of broad-crested weir. Being a weir, the flood discharge over the embankment is only a function of the upstream depth for free flow conditions. This paper will present a method for determining the discharge under submerged flow conditions using the upstream and downstream depths. Thus, postflood field measurements and observations, when properly obtained, will provide the necessary information for an accurate determination of the flood discharge for either free or submerged flow conditions. One of the earliest studies regarding flow over an embankment was reported by Yarnell and Nagler. More recent experimental data have been reported by Kindsvater. The data collected by Kindsvater have been reanalyzed in this paper according to recent developments. The experimental models studied by Kindsvater are comparable to a secondary highway embankment. The data resulting from the model studies have been subjected to the method of submerged flow analysis previously employed with flow measuring flumes. The consistency of the data, both for free flow and submerged flow, reflects the quality of the experimental design and procedures used in collecting the data. Although the data presented in this paper apply only to various forms of secondary road embankments, the method of analysis is general
Subcritical Flow Over Various Weir Shapes
Submerged flow exists for any given structure when a change in flow depth downstream from the structure causes a change in flow depth upstream from the structure for any given constant value of discharge. The two flow depths, normally measured when submerged flow exists, consist of a depth upstream from the structure, which is used also for free flow conditions, and a depth of flow located any place downstream from the structure. The initial studies in which the submerged flow analysis was developed were made on flat-bottomed flumes (Hyatt, 1965; and Skogerboe, Walker, and Robinson, 1965). Later studies verified the method of analysis for Parshall flumes (Skogerboe, Hyatt, England, and John son, 1965; and Hyatt, Skogerboe, and Eggleston, 1966). Because of previous findings, it was felt this method of analyzing submerged flow could be applied to various types and kinds of weirs. Original development of the parameters and relationships which describe submerged flow came from a combination of dimensional analysis and empiricism. Further verification of the parameters developed in this manner are obtained by employing momentum relationships. Both approaches to the submerged flow problem are discussed in this report. Considerable effort and study has been expended on free and submerged flow weirs by other authors in previous years. For this reason the authors of this report went to the literature as a source of data. Various studies typifying a particular type of weir structure were investigated and the data selected from these studies were subjected to the submerged flow analysis developed by the authors. The data from these studies provide further verification of validity of the approach to the submerged flow problem made by the authors. Acknowledgement is given and appreciation expressed to those authors whose studies provided the data used in the analysis presented in this report. Although no investigation was made of a contracted weir, the authors feel that the submerged flow analysis as explained in this report would be just as valid for this type of structure
Design and Calibration of Submerged Open Channel Flow Measurement Structures: Part 1 - Submerged Flow
Stage-Fall-Discharge Relations For Flood Flows Over Highway Embankments
At Utah State University, considerable effort has been devoted to the analysis of submerged flow at open channel constrictions. A method of analyzing submerged flow was first developed for a trapezoidal flume by Hyatt (1965). Later studies verified the method of analysis for a rectangular flume (Skogerboe, Walker, and Robinson, 1965) and Parshall flumes (Skogerboe, Hyatt, England, and Johnson, 1965). Because of the previous findings, it was felt this method of analyzing submerged flow could be applied to highway embankments.
A highway embankment is a form of broad-crested weir when overtopped by flood waters. Being a weir, the flood discharge over the embankment is only a function of the upstream depth for free flow conditions. This report will present a method for determining the discharge under submerged flow conditions using the upstream and downstream depths. Thus, post flood field measurements and observations, when properly obtained, will provide the necessary information for an accurate determination of the flood discharge for either free or submerged flow conditions.
The concepts involved in the analysis of submerged flow at open channel constrictions were originally developed by dimensional analysis for flow measuring flumes. The parameters describing submerged flow in flumes have been further verified by the development of theoretical submerged flow equations which utilize momentum theory and energy relationships.
The experimental models studied by Kindsvater (1964) are comparable to a secondary highway embankment. The models were constructed to a scale of 1/9 a typical secondary roadway. The data resulting from the model studies has been subjected to the method of submerged flow analysis previously employed with flow measuring flumes. The consistency of the data, both fro free flow and submerged flow, reflects the quality of the experimental design and produces employed in collecting the data. Although the data presented in this report applies only various forms of secondary road embankments, the methods of analysis are general. The development of calibration curves for other embankment geometries requires only the generation of additional data employing model studies
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