Economic costs of conventional surface-water treatment: A case study of the Mcallen northwest facility

Conventional water treatment facilities are the norm for producing potable water for U.S. metropolitan areas. Rapidly-growing urban populations, competing demands for water, imperfect water markets, and uncertainty of future water supplies contribute to high interests in alternative sources of potable water for many U.S. municipalities. In situations where multiple supply alternatives exist, properly analyzing which alternative is the most-economically efficient over the course of its useful life requires a sound economic and financial analysis of each alternative using consistent methodology. This thesis discusses such methodology and provides an assessment of the life-cycle costs of conventional water treatment using actual data from an operating surface-water treatment facility located in McAllen, Texas: the McAllen Northwest facility. This facility has a maximum-designed operating capacity of 8.25 million gallons per day (mgd), but due to required shutdown time and other limitations, it is currently operating at 78% of the designed capacity (6.44 mgd). The economic and financial life-cycle costs associated with constructing and operating the McAllen Northwest facility are analyzed using a newly-developed Excel 2 spreadsheet model, CITY H O ECONOMICS . Although specific results are applicable only to the McAllen Northwest facility, the baseline results of 771.67/acre-foot (acft)/ yr {2.37/1,000 gallons/yr} for this analysis provide insight regarding the life-cycle costs for conventional surface-water treatment. The baseline results are deterministic (i.e., noninclusive of risk/uncertainty about datainput values), but are expanded to include sensitivity analyses with respect to several critical factors including the facility’s useful life, water rights costs, initial construction costs, and annual operations and maintenance, chemical, and energy costs. For example, alternative costs for water rights associated with sourcing water for conventional treatment facilities are considered relative to the assumed baseline cost of $2,300/ac-ft, with results ranging from a low of$653.34/ac-ft/yr (when water rights are $2,000/ac-ft) to a high of$1,061.83/ac-ft/yr (when water rights are $2,600/ac-ft). Furthermore, modifications to key data-input parameters and results are included for a more consistent basis of comparison to enable comparisons across facilities and/or technologies. The modified results, which are considered appropriate to compare to other similarly calculated values, are$667.74/ac-ft/yr {2.05/1,000 gallons/yr}

Identifying Most Economic Sources of Potable Water-Case Study in the Rio Grande Valley of Texas

Economic analysis and capital budgeting methods are utilized to analyze the costs of desalinated water relative to conventionally-treated surface water originating from the Rio Grande. Sensitivity analyses are used to evaluate alternative prices for water rights associated with sourcing water for conventional municipal treatment plants

Economic and Financial Methodology for South Texas Irrigation Projects – RGIDECON©

(originally published October 2002

An Overview of Operational Characteristics of Selected Irrigation Districts in the Texas Lower Rio Grande Valley: Delta Lake Irrigation District

Population expansion and water shortfalls have placed the Texas Lower Rio Grande Valley (Valley) center stage in water publicity. The unique characteristics and lack of public knowledge on how irrigation districts divert and convey water from the Rio Grande to municipal, industrial, and agriculture consumers have precipitated questions regarding the operations and makeup of these districts. Differences between and similarities across irrigation districts can be partially attributed to the topography, water-delivery infrastructure system, past financial decisions, and population demographics and clientele base of each irrigation district. Delta Lake Irrigation District (DLID) is one of the 29 irrigation districts in the Valley. This study presents an overview of DLID that includes a brief historical background, a description of the District, and discussion of the District’s current operations. Specific information in the report details how the District diverts and delivers its allocated water from the Rio Grande, how it is used (i.e., municipal, industry, and agriculture), and mechanisms for allocation within and outside the District. The uniqueness of the Lower Rio Grande Valley irrigation districts requires an understanding of their origins and operating mannerisms to explain their overall institutional effects. Through unlocking some of the conundrum associated with these individual irrigation districts, policymakers and other interested stakeholders will have a better perception of the culture and evolution that surround these unique districts, thereby facilitating improved policy-making decisions affecting the region’s water supply and usage

First Sagittarius A* Event Horizon Telescope results. II. EHT and multiwavelength observations, data processing, and calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*'s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior.http://iopscience.iop.org/2041-8205Physic

First Sagittarius A* Event Horizon Telescope Results. II. EHT and Multiwavelength Observations, Data Processing, and Calibration

We present Event Horizon Telescope (EHT) 1.3 mm measurements of the radio source located at the position of the supermassive black hole Sagittarius A* (Sgr A*), collected during the 2017 April 5–11 campaign. The observations were carried out with eight facilities at six locations across the globe. Novel calibration methods are employed to account for Sgr A*'s flux variability. The majority of the 1.3 mm emission arises from horizon scales, where intrinsic structural source variability is detected on timescales of minutes to hours. The effects of interstellar scattering on the image and its variability are found to be subdominant to intrinsic source structure. The calibrated visibility amplitudes, particularly the locations of the visibility minima, are broadly consistent with a blurred ring with a diameter of ∼50 μas, as determined in later works in this series. Contemporaneous multiwavelength monitoring of Sgr A* was performed at 22, 43, and 86 GHz and at near-infrared and X-ray wavelengths. Several X-ray flares from Sgr A* are detected by Chandra, one at low significance jointly with Swift on 2017 April 7 and the other at higher significance jointly with NuSTAR on 2017 April 11. The brighter April 11 flare is not observed simultaneously by the EHT but is followed by a significant increase in millimeter flux variability immediately after the X-ray outburst, indicating a likely connection in the emission physics near the event horizon. We compare Sgr A*’s broadband flux during the EHT campaign to its historical spectral energy distribution and find that both the quiescent emission and flare emission are consistent with its long-term behavior