Vicente L. Lopes

A Systems Approach to Understanding the Evolution of the Agro-Social-Ecological System of the Upper Rio Grande-San Luis Valley, Colorado

Understanding the complex dynamics of social-ecological systems (SES) is difficult because rigorous methodologies and methods for this purpose are lacking. Multi-scale (temporal and geographical) linkages and pathways can mask feedbacks. Thus, understanding SES requires multi-dimensional analyses. This study presents a potential methodology and method for multi-dimensional analyses of a SES in the Upper Rio Grande-San Luis Valley (URG-SLV), Colorado. A driver identification process identified 5 major drivers in the URG-SLV, including stream flow, climate, agriculture, and endogenous and exogenous policy. Several of these drivers possessed more than one longitude. Data for these drivers begins as early as 1852 and extends to 2007. Changes in driver longitudes (long-term datasets within a single driver; maximum, minimum and mean annual temperature comprise climate longitudes) were detected via change point analysis, occurring at several transitional points. Linkages were defined using known relationships between drivers (e.g., stream flow and water rights). Cross-scale relationships between the URG-SLV and downstream users through policy changes and climate also presented a temporal cross-scale linkage. Using the relationships and cross-scale linkages, a historical evolution of the system was constructed throughout the 150-plus years of record to illustrate the effects of changes in drivers and cross-scale linkages in the system.

Semiquantitative Analysis of Water Appropriations and Allocations in the Upper Rio Grande Basin, Colorado

AbstractA semiquantitative analysis was used to assess the impacts of water rights appropriations and allocations in the Upper Rio Grande (URG) Basin, in Colorado. The study also explores the causes and effects of the changes on collateral elements in the URG agriculture system, namely the San Luis Valley (SLV) in Colorado. Population increases, after the acquisition of the territory from 1854 to 1900, were the major cause of increased acquisitions of surface water rights. By 1912 surface waters were nearly 100% appropriated. The population continued to increase until 1930 after which it remained stable. Water users began making large increases in the number of appropriations of groundwater around 1925, with the majority of increases starting around 1935. As a result, moratoriums were placed on well development in the 1970s and 80s. Individual spikes in water rights acquisitions of surface and groundwater were associated with periodic droughts and high crop prices. Change point time series analysis identi...

RELIABILITY ANALYSIS OF URBAN RAINWATER HARVESTING FOR THREE TEXAS CITIES

The purpose of this study was to inform decision makers at state and local levels, as well as property owners about the amount of water that can be supplied by rainwater harvesting systems in Texas so that it may be included in any future planning. Reliability of a rainwater tank is important because people want to know that a source of water can be depended on. Performance analyses were conducted on rainwater harvesting tanks for three Texas cities under different rainfall conditions and multiple scenarios to demonstrate the importance of optimizing rainwater tank design. Reliability curves were produced and reflect the percentage of days in a year that water can be supplied by a tank. Operational thresholds were reached in all scenarios and mark the point at which reliability increases by only 2% or less with an increase in tank size. A payback period analysis was conducted on tank sizes to estimate the amount of time it would take to recoup the cost of installing a rainwater harvesting system.