Lag Time Characteristics of Small Arid and Semiarid Watersheds in the Southwestern United States

Persistent Link:
http://hdl.handle.net/10150/311345
Title:
Lag Time Characteristics of Small Arid and Semiarid Watersheds in the Southwestern United States
Author:
Garcia Mendoza, Jesus Guillermo
Issue Date:
2013
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
An evaluation for Lag time, defined as the time from the centroid of rainfall excess to the centroid of direct runoff, was performed for seven small watersheds in the Southwestern United States. The size of these watersheds range in size from 0.33 to 4.37 ha. The evaluation period goes from 2000 to 2010. This evaluation was compared versus 28 lag time equations.The USDA-ARS Southwest Watershed Research Center has developed an electronic data processing system where rainfall and runoff data is collected from sensors in the field and are transmitted to computers in the office.Prior to these data sets there were no measurable rainfall and runoff data. This digital data is generated by means of synchronized clocks in rain gages and flumes. As a result, the data from this electronic processing system offers a unique opportunity for hydrologic research. This infrastructure is a characteristic not often available in many other sites and a condition not enjoyed in previous investigations.There are several definitions of lag time depending on what particular time period is used to describe the occurrence of unit rainfall and runoff. But, time parameters currently lack commonly-accepted standard definitions.The various definitions for time parameters such as Lag Time, Time of Concentration, Time to Peak, Equilibrium Time and others, sometimes, are used interchangeably. Another aspect is that in Lag time determination, centers of mass play a critical role. This study found out that depending of the loss model chosen to estimate rainfall excess, it shall influence the determination of center of mass and hence the lag time.Some negative values were obtained for lag time when measured from peak of runoff to centroid of effective rainfall. However, in the lag time definition from centroid of effective rainfall to centroid of direct runoff, negative values were not obtained.One field in particular, time parameters currently lacks commonly-accepted standard definitions. This has become a source of profound confusion in this branch of science to the point where teams of scientists writing about and discussing hydrological Time Parameters can be compared to the aftermath at the Tower of Babel.
Type:
text; Electronic Dissertation
Keywords:
Centers of Mass; Lag Time; Southwestern United States; Time of Concentration; Time Parameters; Agricultural & Biosystems Engineering; Arid lands
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Agricultural & Biosystems Engineering
Degree Grantor:
University of Arizona
Advisor:
Slack, Donald C.

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleLag Time Characteristics of Small Arid and Semiarid Watersheds in the Southwestern United Statesen_US
dc.creatorGarcia Mendoza, Jesus Guillermoen_US
dc.contributor.authorGarcia Mendoza, Jesus Guillermoen_US
dc.date.issued2013-
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractAn evaluation for Lag time, defined as the time from the centroid of rainfall excess to the centroid of direct runoff, was performed for seven small watersheds in the Southwestern United States. The size of these watersheds range in size from 0.33 to 4.37 ha. The evaluation period goes from 2000 to 2010. This evaluation was compared versus 28 lag time equations.The USDA-ARS Southwest Watershed Research Center has developed an electronic data processing system where rainfall and runoff data is collected from sensors in the field and are transmitted to computers in the office.Prior to these data sets there were no measurable rainfall and runoff data. This digital data is generated by means of synchronized clocks in rain gages and flumes. As a result, the data from this electronic processing system offers a unique opportunity for hydrologic research. This infrastructure is a characteristic not often available in many other sites and a condition not enjoyed in previous investigations.There are several definitions of lag time depending on what particular time period is used to describe the occurrence of unit rainfall and runoff. But, time parameters currently lack commonly-accepted standard definitions.The various definitions for time parameters such as Lag Time, Time of Concentration, Time to Peak, Equilibrium Time and others, sometimes, are used interchangeably. Another aspect is that in Lag time determination, centers of mass play a critical role. This study found out that depending of the loss model chosen to estimate rainfall excess, it shall influence the determination of center of mass and hence the lag time.Some negative values were obtained for lag time when measured from peak of runoff to centroid of effective rainfall. However, in the lag time definition from centroid of effective rainfall to centroid of direct runoff, negative values were not obtained.One field in particular, time parameters currently lacks commonly-accepted standard definitions. This has become a source of profound confusion in this branch of science to the point where teams of scientists writing about and discussing hydrological Time Parameters can be compared to the aftermath at the Tower of Babel.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectCenters of Massen_US
dc.subjectLag Timeen_US
dc.subjectSouthwestern United Statesen_US
dc.subjectTime of Concentrationen_US
dc.subjectTime Parametersen_US
dc.subjectAgricultural & Biosystems Engineeringen_US
dc.subjectArid landsen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineAgricultural & Biosystems Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorSlack, Donald C.en_US
dc.contributor.committeememberSlack, Donald Cen_US
dc.contributor.committeememberYitayew, Mulunehen_US
dc.contributor.committeememberWaller, Peteren_US
dc.contributor.committeememberHawkins, Richard H.en_US
dc.contributor.committeememberCanfield, Evan H.en_US
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