Water Conservation, Wetland Restoration and Agriculture in the Colorado River Delta, Mexico

Persistent Link:
http://hdl.handle.net/10150/195396
Title:
Water Conservation, Wetland Restoration and Agriculture in the Colorado River Delta, Mexico
Author:
Carrillo-Guerrero, Yamilett Karina
Issue Date:
2009
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:
In arid lands, wetland loss is the result not only of the scarcity of water itself, but of the management of water to maximize off-stream uses. Declaring a wetland as a protected natural area is not enough when its water supply is not protected as well. In a fully-diverted, over-allocated, drought-prone Colorado River ecosystem, its delta has no instream flows allocated. Water use efficiency (WUE) is touted as the panacea for water shortages and lack of instream flows. I evaluated the relationships between water use in the Mexicali Irrigation District and the water supply for the Colorado River delta wetlands. The survey applied to 521 farmers complemented the GIS analysis to create a spatial distribution of agronomic and socio-economic factors influencing farmers’ options to improve WUE in irrigation. Mexicali farmers apply 10,496 m³/ha/yr; 4% higher than the legal allotment. Still, 28% of the district’s soils are salt-affected (ECe > 8dS/m), 19% are sodic (ESP > 50%), and 39% of the salt load in irrigation water accumulates in the soils. Thus, Mexicali farmers apply more water than plants need in order to maintain the sustainability of their soils. From an agronomic perspective, increasing WUE is feasible in 80% of the valley. However, high costs and lack of technical knowledge limit farmers’ options to either continue using as much water as they do now or rent/sell their water rights to larger farming operations or urban developments. Mexicali’s agriculture provides 87 Mm³ of water to the delta marshes, and seepage from unlined canals and subsurface flows generated by irrigation contribute to sustain riparian areas. Agricultural “inefficiencies” become the main source of water for wetlands when flows are fully diverted. The Irrigation District 014 is an integral part of the delta ecosystem; this is a required change in the agriculture-wetland paradigm. The restoration of arid and over-allocated rivers requires the integration of irrigation practices and WUE with the allocation of water for instream flows. The restoration of wetlands of international watersheds like the Colorado River requires the bi-national collaboration beyond memorandums of understanding between the countries; treaties where environmental flows are actually allocated will better serve shared ecosystems.
Type:
text; Electronic Dissertation
Keywords:
Agriculture; Colorado River delta; Mexico; Water Conservation; Water Use Efficiency; Wetland Restoration
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Natural Resources; Graduate College
Degree Grantor:
University of Arizona
Committee Chair:
Shaw, William W

Full metadata record

DC FieldValue Language
dc.language.isoENen_US
dc.titleWater Conservation, Wetland Restoration and Agriculture in the Colorado River Delta, Mexicoen_US
dc.creatorCarrillo-Guerrero, Yamilett Karinaen_US
dc.contributor.authorCarrillo-Guerrero, Yamilett Karinaen_US
dc.date.issued2009en_US
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.abstractIn arid lands, wetland loss is the result not only of the scarcity of water itself, but of the management of water to maximize off-stream uses. Declaring a wetland as a protected natural area is not enough when its water supply is not protected as well. In a fully-diverted, over-allocated, drought-prone Colorado River ecosystem, its delta has no instream flows allocated. Water use efficiency (WUE) is touted as the panacea for water shortages and lack of instream flows. I evaluated the relationships between water use in the Mexicali Irrigation District and the water supply for the Colorado River delta wetlands. The survey applied to 521 farmers complemented the GIS analysis to create a spatial distribution of agronomic and socio-economic factors influencing farmers’ options to improve WUE in irrigation. Mexicali farmers apply 10,496 m³/ha/yr; 4% higher than the legal allotment. Still, 28% of the district’s soils are salt-affected (ECe > 8dS/m), 19% are sodic (ESP > 50%), and 39% of the salt load in irrigation water accumulates in the soils. Thus, Mexicali farmers apply more water than plants need in order to maintain the sustainability of their soils. From an agronomic perspective, increasing WUE is feasible in 80% of the valley. However, high costs and lack of technical knowledge limit farmers’ options to either continue using as much water as they do now or rent/sell their water rights to larger farming operations or urban developments. Mexicali’s agriculture provides 87 Mm³ of water to the delta marshes, and seepage from unlined canals and subsurface flows generated by irrigation contribute to sustain riparian areas. Agricultural “inefficiencies” become the main source of water for wetlands when flows are fully diverted. The Irrigation District 014 is an integral part of the delta ecosystem; this is a required change in the agriculture-wetland paradigm. The restoration of arid and over-allocated rivers requires the integration of irrigation practices and WUE with the allocation of water for instream flows. The restoration of wetlands of international watersheds like the Colorado River requires the bi-national collaboration beyond memorandums of understanding between the countries; treaties where environmental flows are actually allocated will better serve shared ecosystems.en_US
dc.typetexten_US
dc.typeElectronic Dissertationen_US
dc.subjectAgricultureen_US
dc.subjectColorado River deltaen_US
dc.subjectMexicoen_US
dc.subjectWater Conservationen_US
dc.subjectWater Use Efficiencyen_US
dc.subjectWetland Restorationen_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineNatural Resourcesen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.chairShaw, William Wen_US
dc.contributor.committeememberShaw, William W.en_US
dc.contributor.committeememberGimblett, Randyen_US
dc.contributor.committeememberValdes-Casillas, Carlosen_US
dc.contributor.committeememberSilvertooth, Jeffrey C.en_US
dc.contributor.committeememberGlenn, Edward P.en_US
dc.identifier.proquest10630en_US
dc.identifier.oclc659753427en_US
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