2 edition of **Accuracy of low-flow characteristics estimated by correlation of base-flow measurements** found in the catalog.

Accuracy of low-flow characteristics estimated by correlation of base-flow measurements

Clayton Haines Hardison

- 258 Want to read
- 17 Currently reading

Published
**1972**
by U.S. Govt. Print. Off. in Washington
.

Written in English

- Stream measurements -- Statistical methods.

**Edition Notes**

Bibliography: p. 55.

Statement | by Clayton H. Hardison and Marshall E. Moss. With a section on Outline of derivations, by Edward J. Gilroy. |

Series | Manual of hydrology: part 2. Low-flow techniques, Geological Survey water-supply paper ;, 1542-B |

Contributions | Moss, Marshall E., joint author. |

Classifications | |
---|---|

LC Classifications | TC801 .U2 no. 1542-B, GB1205 .U2 no. 1542-B |

The Physical Object | |

Pagination | iv, 35-55 p. |

Number of Pages | 55 |

ID Numbers | |

Open Library | OL5389156M |

LC Control Number | 72600238 |

There is a broad range of accuracy possible in measurement of flow, from general estimates for planning purposes, to simple measurements that can be done by citizen groups, to detailed scientific measurements conducted by the USGS or other specialists. In many cases, the Quality Assurance Project Plan (QAPP) associated with a particular project. The accuracy of the estimated low-flow characteristics is evaluated according to the type and amount of data available used to determine the low-flow characteristics. The accuracy determined by the standard error of estimate for the year low flow (SE10) ranged from 18 percent at continuous -record gaging stations to 70 percent when only three base-flow measurements were available.

Introduction Determining the Transit Time Reliability and Accuracy Cross-Correlation Flowmeter Designs Ultrasonic Cross-Correlation Flowmeters Partially Filled Pipes and Channels Hot Gas Flow Measurement Nuclear Power Plant Applications TTFM System Speci cation Form Abbreviations Bibliography It was found that the flowmeter can stably measure a flow rate of less than 1 ml/min with a standard deviation of about ml/min. These results suggest that it can measure a sufficiently low flow rate range to be used in the semiconductor, medical and chemical industries. 2. Experimental set-up Test equipment.

LOW-FLOW CHARACTERISTICS OF LOUISIANA STREAMS By Paul A. Ensminger and Lucille S. Wright ABSTRACT The low-flow characteristics were estimated for continuous-record streamflow-gaging stations and partial-record stations in Louisiana. These low-flow characteristics supersede the previously published characteristics. Purchase Fluid Flow Measurement - 2nd Edition. Print Book & E-Book. ISBN ,

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TABLE 2. Accuracy of low-flow characteristics estimated by correlation of base-flow measurements [No is the number of years of record at the gaged site, NU is the accuracy at the ungaged site in equivalent years of record, r is the coefficient of correlation, and F depends on the statistics of the correlation] rWj/, in years, for indicated F 5Cited by: Get this from a library.

Accuracy of low-flow characteristics estimated by correlation of base-flow measurement / With a section on Outline of derivations, by Edward J. Gilroy. [C H Hardison; Edward J Gilroy; Marshall E Moss; Geological Survey (U.S.),]. The accuracy of low-flow characteristics estimated from correlation of base-flow measurements is discussed in Hardison and Moss ().

Ungaged Sites on Gaged Streams The flow-routing method predicts low-flow values fairly well along gaged streams when the basin character istics between the gaged site and ungaged site are homoge neous.

Application of regional equations to estimate low-flow characteristics 3 Limitations and accuracy of equations 3 Estimates for low flow at ungaged sites 5 Verification of regression equations at partial-record sites 5 Plots showing comparison of 3-day year low flow from correlation.

Low flows also are associated with low dissolved oxygen and/or high contaminant concentrations, with negative consequences for aquatic habitat. For these reasons, state and local municipalities establish regulatory limits on the basis of estimated low‐flow characteristics, such as the estimated 7‐day, 10‐year low flow, 7,10 [Riggs, ].Cited by: Accuracy of low-flow characteristics estimated by correlation of base-flow measurements,Water Supply Paper B Geology and ground water of the Molalla-Salem slope area, northern Willamette Valley, Oregon,Water Supply Paper However, he encouraged the collection of additional base-flow measurements as well as data on stream environment, particularly on basin characteristics that control low flows.

These data would be used for advanced research for developing analytical methods that could provide more accurate estimates of low-flow characteristics. [2] Knowledge of the magnitude and frequency of low-flow events is required in order to plan water-supply systems, wastewater discharges, reservoirs, and irrigation systems, and to maintain the quality of water for wildlife and recreation [Smakhtin, ].

In the United States, the 7-day, year low flow (Q 7,10) is a commonly used low. The current study examines baseflow correlation, an alternative method for estimating low‐streamflow statistics that uses the cross‐correlation of a nominal number of baseflow measurements from an ungauged and a nearby gauged river site to estimate the streamflow statistics at the ungauged site [Stedinger and Thomas, ].

The accuracy of the estimated low-flow characteristics is evaluated according to the type and amount of data available used. The statewide average of the accuracy determined by the standard error of estimate for the year low flow (SEys io)> based on three base-flow measurements, is ^ percent but differs within the State.

INTRODUCTION. flow partial-record stations and 70 miscellaneous sites; and a list of low-flow discharge measurements at miscellaneous sites. Relations are provided to estimate low-flow characteristics at ungaged sites and at sites where one base-flow discharge measurement is available.

The relationships were determined from multiple regression analyses. Low-flow characteristics cannot be estimated for regulated streams unless the amount of regulation is known so that the estimated low-flow characteristic can be adjusted.

Introduction. Developing accurate estimates of low streamflows is crucial for effective water resources planning and management (Smakhtin, ).The 7-day, year low flow (Q 7,10) and 7-day, 2-year low flow (Q 7,2) are commonly used low flow statistics in the United States (Riggs, ).The Q 7,10 is the annual 7-day minimum flow that is expected to be exceeded on average in 9.

Standard Deviation Estimate is the measure of dispersion of a set of data in its distribution about the mean of the set and can be expressed as. S = [Σ(q a - q i) 2 / (n - 1)] 1/2 (3) where. S = standard deviation estimate. q a = mean value of measurements.

q i = each individual measurement. Accuracy of low-flow characteristics estimated by correlation of baseflow measurements. US Geol. Surv. Water Supply Pap. Harlin, J., Development of a process oriented calibration scheme for the HBV hydrological model. Low-flow, base-flow, and mean-flow characteristics are an important part of assessing water resources in a watershed.

These streamflow characteristics can be used by watershed planners and regulators to determine water availability, water-use allocations, assimilative capacities of streams, and aquatic-habitat needs.

Streamflow characteristics are commonly predicted by use of regression. Predictive equations for the harmonic mean flow; the 7-day, 2-year low-few (7Q2); and the 7-day, year low-flow (7Q10) of ungauged Texas streams are developed using multiple regression analysis.

Magnetic flowmeters (typically +/- percent of reading over a to-1 turndown) are much more capable of maintaining accuracy at low flow velocities, and they will even provide accurate measurements under less-than-ideal flow profile conditions.

That said, most magmeters will also struggle to deliver accurate measurements at low flow velocities. The low flow indices are then correlated with the catchment characteristics, using statistical software, to develop relationships for estimating low flow indices, at ungauged sites.

It was observed that the models developed were linear, show a very high degree of correlation and can be used for preliminary design at ungauged catchments. into account differences in accuracy of at-site estimates of low flow characteristics, the sample cross correlation between estimates, and the sample autocorrelation of annual minimum flows.

All the techniques are illustrated by a network of gages in central Florida, USA. Logistic regression is used to estimate the probability of zero flow at a. The estimates of low-flow characteristics at short-record sites may be improved by using the information from other gauged sites with longer records (e.g.

Durrans and Tomic, ). Also, various streamflow record augmentation procedures may be employed to increase the effective record length (Vogel and Stedinger,Vogel and Kroll, ). Ensembles of artificial neural networks (ANNs; obtained by subsampling the original set of catchments) were trained to estimate the base flow characteristics from climatic and physiographic data.

The catchment‐scale estimation of the base flow characteristics demonstrated encouraging performance with R 2 values of for BFI and for k.Accuracy of Low-Flow Characteristics Estimated by Correlation of Base-Flow Measurements: Manual of Hydrology: Part 2.

Low-Flow Techniques Clayton H. Hardison, Marshall E. Moss.