Repository logo

Browsing by Author "Goemans, Chris, committee member"

Now showing 1 - 10 of 10
  • Thumbnail Image
    ItemOpen Access
    A collaborative planning framework for integrated urban water management with an application in dual water supply: a case study in Fort Collins, Colorado
    (Colorado State University. Libraries, 2018) Cole, Jeanne Reilly, author; Sharvelle, Sybil, advisor; Grigg, Neil, advisor; Arabi, Mazdak, committee member; Goemans, Chris, committee member
    Urban water management is essential to our quality of life. As much of our urban water supply infrastructure reaches the end of its useful life, water managers are using the opportunity to explore alternative strategies that may enable them to better meet modern urban water challenges. Water managers must navigate the labyrinth of balancing stakeholder needs, considering all costs and benefits, reducing decision risk, and, most importantly, ensuring public health and protecting the environment. Innovative water managers need guidance and tools to help manage this complex decision space. This dissertation proposes a collaborative, risk-informed, triple bottom line, multi-criteria decision analysis (CRTM) planning framework for integrated urban water management decisions. The CRTM framework emerged from the obstacles and stakeholder needs encountered during a study evaluating alternative dual water supply strategies in Fort Collins, Colorado. The study evaluated four strategies for the dual supply of raw and treated water including centralized and decentralized water treatment, varying distribution system scales, and integration of existing irrigation ditches with raw water landscape irrigation systems. The results suggest that while the alternative dual water supply strategies offer many social and environmental benefits, the optimal strategies are dependent on local conditions and stakeholder priorities. The sensitivity analysis revealed the key parameters driving uncertainty in alternative performance were regulatory and political reinforcing the importance of participation from a wide variety of stakeholders. Evaluation of the decision process suggests the CRTM framework increased knowledge sharing between study participants. Stakeholder contributions enabled a comprehensive evaluation of the option space while examining the financial, social and environmental benefits and trade-offs of the alternatives. Most importantly, evolving the framework successfully maintained stakeholder participation throughout the study.
  • Thumbnail Image
    ItemOpen Access
    Accounting for spatial substitution patterns and bioeconomic feedback loops: an economic approach to managing inland recreational fisheries
    (Colorado State University. Libraries, 2011) Deisenroth, Daniel B., author; Bond, Craig A., advisor; Loomis, John B., advisor; Goemans, Chris, committee member; Davies, Stephen, committee member; Myrick, Chris, committee member
    This dissertation consists of three papers which address separate but related issues in recreational fisheries management. Paper one estimates the economic contribution of the private, recreation-based aquaculture industry in the Western United States. Paper two presents a method for combining models of site selection with input-output models in order to better estimate the true economic impacts of augmentation or deterioration of recreational sites. Finally, paper three presents a dynamic, bioeconomic model of a recreational fishery and uses that model to simulate what would happen over time to anglers and fish populations (as well as value to anglers) if fish stocking were to be halted at a single recreational fishery. All three papers are policy relevant today given the increased pressure from (and litigation filed by) environmental groups to reduce fish stocking due to conflicts with native and endangered species. Paper one explores the economic contribution of the private, recreation-based aquaculture industry in the Western United States. New sectors are constructed in IMPLAN input-output software using data gathered between 2007 and 2010 from producers and their direct customers (stocked fisheries). Information from a third survey of anglers in Colorado and California is integrated to predict the short-term shocks that would occur to various industries if anglers at privately stocked fisheries were to discontinue fishing (simulating a hypothetical collapse of the industry). Accounting for both the backward and forward linkages of the private, recreation-based aquaculture industry's production, model results indicate that for every dollar of fish stocking, $36 dollars of recreational angler-related expenditures are supported, and that the total economic contribution of this industry in the Western United States is roughly $2 billion annually. This is the first study addressing the forward linkages and total economic contribution of this industry in the Western United States. Paper two addresses a similar issue as paper one, but goes further to account for substitution patterns among anglers. Using information from a survey of anglers in 2009, a repeated nested logit (RNL) model of angler spatial substitution behavior is estimated. Then, the RNL is used to predict changes in angler days associated with changes in fishery attributes. By linking the RNL and input-output model, better insight is gained into the economic losses associated with augmentation or deterioration of stocked fishing sites. Results indicate that if a single site is closed within the region of analysis, of the 29,500 anglers that will no longer fish at that site, only 6,500 anglers will leave the region of analysis (the rest substituting to other in-region sites). Standard impact analysis would therefore overestimate the economic impacts of such a policy by 450%. Results are similar when catch rates are reduced by 50% at one site, with 14,000 anglers leaving that site but only 3,000 leaving the region. The third and final paper of this dissertation presents a means by which managers may manage inland recreational fisheries from a dynamic bioeconomic perspective. A discrete-time, discrete-space, infinite time horizon numerical model of a fishery is built in GAMS software to reflect responses of anglers to the fishery and responses of the fishery to anglers over time. A data-driven random utility model is used to inform angler response and value functions in this dynamic bioeconomic model. Results from one region in California indicate that a) current fish stocking levels may be inefficiently high, and b) elimination of fish stocking programs at popular lakes may not lead to a crash in fishery populations, since anglers will simply substitute to other nearby fisheries (rather than "fish-out" the lake). Managers who can predict the intertemporal effects of fishery management alternatives in this way will be able to better meet the demands of recreational anglers.
  • Thumbnail Image
    ItemOpen Access
    An analysis of the impact of land tenure on groundwater use and attitudes concerning groundwater conservation in Colorado's Republican River Basin
    (Colorado State University. Libraries, 2017) Shepler, Ryan, author; Suter, Jordan, advisor; Goemans, Chris, committee member; Schneekloth, Joel, committee member
    Groundwater pumping from an aquifer that exceeds the recharge rate results in decreases in future groundwater availability and well capacity. Economic research on groundwater pumping has generally assumed that groundwater is being managed myopically (Koundouri, 2004). Further research with the Ogallala aquifer has found contradictory results, with research from Pfieffer and Lin (2013) suggesting that there is dynamic decision making, while other empirical analysis has lead researchers to conclude there is no difference between myopic decision making and an otherwise optimal groundwater extraction strategy (Savage, 2011). Our research within the Republican River Basin of Colorado contributes to the literature by analyzing the impacts of land tenure on the extent to which tenants and owners make dynamically informed decisions. We find no evidence of heterogeneity in groundwater use as a result of land tenure, suggesting that groundwater decisions are being made myopically. Our research also uses data from a recently conducted survey within the region to examine the impact that tenure has in determining concern regarding groundwater availability, and support for policies within the region that would seek to conserve groundwater. Estimating multiple probit regressions, we find that tenant operators are less likely to be concerned about the long-term availability of groundwater, and that they are less likely to support groundwater management districts working to develop strategies that would seek to promote groundwater conservation. We do not find that tenure has an impact on support for specific policy mechanisms, but rather that well capacity is pivotal in driving support for these specific policies.
  • Thumbnail Image
    ItemOpen Access
    Considerations for implementing source separation and treatment of urine, graywater, and blackwater
    (Colorado State University. Libraries, 2015) Fewless, Kimberly LeMonde, author; Sharvelle, Sybil, advisor; Bledsoe, Brian, committee member; Goemans, Chris, committee member
    Source separation integrated with decentralized wastewater treatment offers the possibility of recovering nutrients, reducing release of micropollutants to the environment, and increasing water recycling more efficiently than centralized wastewater treatment. Nutrient effluent discharge limits and guidelines for wastewater treatment plants are becoming stricter, and nutrient removal or recovery is very costly for the large volumes present. This is driving innovation in wastewater treatment. Three waste streams are identified for potential source separation and treatment: urine, graywater (non-kitchen sinks, showers/bath, and laundry), and blackwater (feces and kitchen wastewater). Urine is only 1% of the domestic wastewater stream, but contains 50-80% of the nutrients (nitrogen, phosphorus, and potassium) and the majority of pharmaceuticals and hormones. Blackwater has high organic and nutrient content, solids, and pathogens, and carries the remaining pharmaceutical/hormone residues. Graywater is the largest contributor to total volume but is the least contaminated of the three streams (low in nutrients and pathogens, but contains detergents and personal care products). In the absence of kitchen wastewater, graywater is also low in organic content. If these streams are separated at the source, maximum reuse of water can be achieved with minimal treatment (e.g. graywater). More importantly, avoiding dilution of nutrients and pharmaceuticals/hormones allows for more advanced treatment without excess cost. A literature review led to the conclusion that the best options for urine treatment are struvite precipitation for phosphorus recovery and ammonia stripping for nitrogen recovery. Anaerobic digestion is ideal for blackwater and constructed wetlands can be used for graywater treatment. A neighborhood system of 500-1000 homes with decentralized treatment of urine, graywater, and blackwater is proposed. Almost complete recovery of nutrients could be achieved from urine, graywater could be treated and “locally” recycled, and energy and nutrients could be recovered from blackwater. A wastewater treatment system combining these components has not yet been tested in a pilot project; however, the individual treatment systems have been operated in pilot projects (or at larger scales) with similar waste streams. Modification of regulatory framework will be necessary to accommodate water reuse and effluent regulations at the proposed decentralized scale. Although nutrient reuse is a goal in the proposed system, farmer and consumer acceptance in the U.S. are unknown, but critical. Technical obstacles to implementation include improving urine diversion toilets and treatment systems (primarily decreasing maintenance and increasing automation), managing urine scale (spontaneous precipitation in pipes), avoiding or capturing volatilized ammonia in urine transport, and better characterizing waste streams for treatment optimization. Research and development should focus on decreasing maintenance of urine diversion components and increasing automation. It is also necessary to better define influent quality and effluent goals and to optimize treatment systems for the proposed configuration. The waste stream produced from urine treatment also needs consideration, as it is likely to by highly concentrated with pharmaceuticals. A pilot project in the U.S. is recommended to resolve technical issues. A preliminary review of costs reveals that, as is typically the case with new technologies, urine diversion toilets and struvite precipitation reactors have high investment and operational costs. Despite this, early estimates indicate that urine diversion systems are less costly than adding nutrient removal in wastewater treatment plants. In addition, the high costs of urine diversion systems are largely due to maintenance requirements and economies of scale (aspects that will change with research and development). In moving forward, it will be beneficial to conduct an economic analysis of greater breadth, with consideration of water reuse, energy use/carbon footprint, cost of fertilizer production, potential revenue of recovered nutrients, and economic externalities. It is also important to consider the reality of transition: that unless conventional wastewater treatment becomes more expensive (due to nutrient regulations) or homeowners are willing to cover the extra cost of a decentralized system with urine diversion, developers/homeowners are likely to choose tapping into the current system. Although technical issues are pressing and infrastructure requirements are extensive for the proposed decentralized system, the technical, social, and regulatory issues are not insurmountable. The potential in improved treatment (nutrient and micropollutant removal), energy generation and increased water recycling suggests moving forward with research and development in the U.S., including a pilot project.
  • Thumbnail Image
    ItemOpen Access
    Evaluating the efficiency of conservation efforts: a frontier regression approach
    (Colorado State University. Libraries, 2012) Keenan, Andrew, author; Kling, Robert, advisor; Anderson, Aaron, committee member; Goemans, Chris, committee member; Pena, Anita, committee member
    Conservation efforts in the United Kingdom began in 1949 with the Nature Conservancy Act. The goals of this legislation were to preserve natural areas and areas inhabited by threatened and endangered species, as well as provide the opportunity for research. The objective of this thesis is to apply stochastic frontier analysis (SFA) to better evaluate the efficiency of threatened and endangered species conservation efforts. SFA will build upon previous analysis that uses cost-utility analysis to measure the effectiveness of a Species Action Plan (SAP). This new application of a SFA will help improve the assessment of efficiency of government programs, and is an improvement from existing conservation efficiency measures because the analysis does not require assumptions of the value of a species. The absence of assumptions on value helps the analysis reflect actual funding decisions and better allows for interspecies comparisons. The results will not only provide a more robust analysis, but also have practical application in evaluating the efficiency of a species recovery and give conservation efforts a better measurement tool. With an effective efficiency measure in place, programs will be better judged and shifts in funding or changes to specific plans are possible.
  • Thumbnail Image
    ItemOpen Access
    Evaluation of cost effective approaches for nutrient removal in urban stormwater and wastewater: City of Fort Collins case study
    (Colorado State University. Libraries, 2015) Breidt, Sarah, author; Sharvelle, Sybil, advisor; Roesner, Larry, committee member; Goemans, Chris, committee member
    To respond to pending regulation that affects effluent nitrogen and phosphorus standards from urban watersheds, this study compares existing nutrient discharges from wastewater and stormwater sources in Fort Collins, Colorado and evaluates the benefits and costs of nutrient removal strategies identified in both sectors as a guide to urban planners. Six alternative wastewater advanced nutrient removal technologies were modeled in BioWin® to be integrated with the existing modified Bardenpho unit. Approximately 1,500 stormwater control measures (SCMs) are implemented in Fort Collins at present; however, not all provide water quality treatment. Two alternative stormwater scenarios were evaluated using the Simple Method and include: 1) retrofitting existing flood control SCMs to provide treatment, and 2) implementing SCMs to treat runoff from currently untreated impervious areas. Treatment level, environmental impacts, and 20-year lifecycle costs were determined for all alternatives and compared within a multi-criterion decision analysis (MCDA). Existing wastewater discharges of nitrogen and phosphorus are 2.0 and 1.5 times larger than those from stormwater, respectively. Removal efficiencies from these discharge nutrient levels were found to be between 7.5% and 30% for wastewater and 20% and 35% for stormwater. Although wastewater alternatives had large ranges of potential costs, all were determined to be more cost effective ($/lb. removal) than the stormwater scenarios. Struvite precipitation in all MCDA scenarios is the most advantageous alternative, followed by ammonia stripping and extended detention basin (EDB) retrofits.
  • Thumbnail Image
    ItemOpen Access
    Heterogeneity in the price elasticity of demand for commercial water
    (Colorado State University. Libraries, 2018) Flyr, Matthew, author; Burkhardt, Jesse, advisor; Goemans, Chris, committee member; Shields, Martin, committee member
    The gap between projected future water demand and supply are increasing the importance of conservation policies. Commercial users are a major source of utility withdrawals, heightening the need for increased understanding of commercial responsiveness to utility policies. Despite an abundance of empirical studies on residential water demand, there are limited commercial sector studies exploring demand elasticity heterogeneity. In this paper, we estimate commercial water demand elasticity for firms served by a local utility, employing a novel instrumental variables approach. We then present evidence that firms respond to one period lagged average price rather than marginal price. Finally, we find notable differences in elasticity among different categories of businesses and among businesses of different consumption variance levels. The findings in this paper are particularly important as utility providers across the country consider how to cope with growing demand and limited water supply.
  • Thumbnail Image
    ItemOpen Access
    Measuring and modeling geosmin removal from Horsetooth Reservoir water by powdered activated carbon for selected contact times
    (Colorado State University. Libraries, 2011) Koester, Kirk, author; Omur-Ozbek, Pinar, advisor; Carlson, Ken, committee member; Goemans, Chris, committee member
    Presence of geosmin, an odorous algal metabolite produced by cyanobacteria and actinomycetes, has been an issue in drinking waters in Northern Colorado. Geosmin does not pose a health threat; however, it imparts an earthy taste and odor to the finished drinking water even at very low concentrations (4 -10 ng/L), resulting in consumer complaints and dissatisfaction. Geosmin cannot be removed by conventional water treatment processes, so further treatment is required to achieve concentrations below detection limits. This study investigated the geosmin removal from the raw water obtained from the Horsetooth Reservoir, in Fort Collins, CO by powdered activated carbon (PAC). Raw water samples were spiked with stock geosmin solution to obtain concentrations from 10 to 50 ng/L and stock PAC solution to obtain concentrations from 5 to 20 mg/L. Thirteen different geosmin/PAC concentrations were tested for 90 minutes contact time (and up to 6 hours for selected combinations) and the geosmin removal was determined by headspace solid phase microextraction and gas chromatography/mass spectrometry. Results indicated that 50 to 70% removal was achieved for lower doses of geosmin/PAC combinations, and 80 to 97% removal was achieved for higher PAC dose combinations. Most (65%) of the geosmin removal was achieved within the first thirty minutes. For 54% of the samples, geosmin concentrations in the treated water were lowered below 4 ng/L after 90 minutes, which is a low enough concentration to prevent consumer complaints. Furthermore, 38% of the samples lowered geosmin concentrations below 4 ng/L after 45 minutes. Additionally three PAC/geosmin combinations that contained 8 mg/L of total organic carbon were examined and a decrease in geosmin removal by 8-12% after 90 minutes was observed. Further analysis with Stat-Ease® Design Expert® (v.8) was used to model geosmin removal to predict required PAC dosages for geosmin levels not tested in this study. The model developed by the Design Expert® considered the initial geosmin concentration, PAC dosing and contact time, and a simple equation was obtained to predict the remaining geosmin concentrations in the treated water. Results from the model fit the data obtained from laboratory measurements and reliably predicted geosmin removal for concentrations not tested.
  • Thumbnail Image
    ItemOpen Access
    Raw material optimization and CO₂ sensitivity-predictive analytics in cement manufacturing: a case study at Union Bridge Plant, Heidelberg Materials, Maryland
    (Colorado State University. Libraries, 2024) Boakye, Kwaku, author; Simske, Steve, advisor; Bradley, Tom, committee member; Troxell, Wade, committee member; Goemans, Chris, committee member
    Cement has been in use by humans throughout history, and its manufacturing process has undergone many changes. The high increase in economic growth around the world and the demand for rapid infrastructure development due to population growth are the underlying reasons for the globally high cement demand. Cement is produced by grinding clinker together with a mixture of ground gypsum. The clinker is produced using a rotary kiln which burns a mixture of limestone, clay, magnesium, silica, and iron with desired atomic percentages through the calcination process. The quarry serves as the main source of raw material for the rotary kiln in cement production. Over the years cement manufacturing has hurt environmental, social, and political aspects of society. This negative impact includes the overuse of raw material which is obtained by mining resulting in disturbed landmass, overproduction of rock waste material, and the emission of CO2 resulting from the calcination of limestone in the pyro process. The study looks at three cement manufacturing systems and uses different methodologies to achieve results that can be implemented in the cement industry. These three systems were (1) the quarry (2) the preheat tower and (3) the kiln. Ensuring the consistency of material feed chemistry, with the quarry playing a pivotal role, is essential for optimizing the performance of a rotary kiln. The optimization of the raw material also allows limited use of raw materials for cement manufacturing, cutting down waste. The study employed a six-step methodology, incorporating a modified 3D mining software modeling tool, a database computer loop prediction tool, and other resources to enhance mining sequencing, optimize raw material utilization, and ensure a consistent chemistry mix for the kiln. By using overburden as a raw material in the mix, the quarry nearly universally reduced the environmental impact of squandering unwanted material in the quarry. This has a significant environmental impact since it requires less space to manage the overburdened waste generated during mining. In addition, raw material usage was optimized for clinker production, causing a reduction of 4% in sand usage as raw material, a reduction in raw material purchase cost, a reduction of the variability of kiln feed chemistry, and the production of high-quality clinker. The standard deviation of kiln feed LSF experienced a 45 percent improvement, leading to a 65 percent reduction in the variability of kiln feed. The study also uses machine learning methods to model different stages of the calcination process in cement and to improve knowledge of the generation of CO2 during cement manufacturing. Calcination plays a crucial role in assessing clinker quality, energy requirements, and CO2 emissions within a cement-producing facility. However, due to the complexity of the calcination process, accurately predicting CO2 emissions has historically been challenging. The objective of this study is to establish a direct relationship between CO2 generation during the raw material manufacturing process and various process factors. In this paper, six machine-learning techniques are explored to analyze two output variables: (1) the apparent degree of oxidation, and (2) the apparent degree of calcination. Sensitivity analysis of CO2 molecular composition (on a dry basis) utilizes over 6000 historical manufacturing health data points as input variables, and the findings are utilized to train the algorithms. The Root Mean Squared Error (RMSE) of various regression models was examined, and the models were then run to ascertain which independent variables in cement manufacturing had the largest impact on the dependent variables. To establish which independent variable had the biggest impact on CO2 emissions, the significance of the other factors was also assessed.
  • Thumbnail Image
    ItemOpen Access
    The cost of consumption: an analysis of the heterogeneous impacts of groundwater availability in the High Plains aquifer
    (Colorado State University. Libraries, 2019) Moore, Lacey, author; Suter, Jordan, advisor; Goemans, Chris, committee member; Schipanski, Meagan, committee member
    Nearly 20-percent of the wheat, corn, cotton and cattle produced in the United States are made possible by the hydrologic resources of the High Plains Aquifer (HPA) (NRCS, 2017). Despite being a source of agricultural prosperity, this aquifer has long been subject to overdraft including reductions in saturated thickness exceeding 50m in the southern extents (Haacker et al., 2016). We follow Hornbeck et al. (2014, 2015) in comparing economic outcomes among counties inside the HPA to similar counties within 100km from the aquifer boundary, building on this research by also evaluating the impact of initial groundwater endowments as an exogenous measure of irrigation access. Utilizing a hedonic pricing model based on Ricardian theory of land valuation, we choose to examine irrigation intensity, land values, and population density using census data at the county scale to measure the marginal benefit of groundwater. These economic outcomes are examined across ranked groupings of initial saturated thickness for three distinct time periods: approximate pre-development of the aquifer (1925-1945), during the height of irrigation expansion (1950-1992), and during contemporary time periods of irrigation water shortages (1997-2012). Results indicate that previous studies which have regarded the HPA as a homogeneous unit overlook the true marginal contributions of groundwater. We find that the counties with the largest initial endowments of groundwater in the HPA have increased land values by as much as 42-percent during the height of irrigation expansion, and more importantly have maintained the longest lasting economic benefits compared to counties with lower initial saturated thickness and those outside the aquifer. Our results differ from previous studies (i.e., Feng et al., 2012) as we find no statistical relationship between access to groundwater (or aquifer depletion) and population density.