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Storage and release functions of western U.S. traditional river valley irrigation systems may counteract early and rapid spring river runoff associated with climate variation. Along the Rio Grande in northern New Mexico, we instrumented a 20-km-long irrigated valley to measure water balance components from 2005 to 2007. Hydrologic processes of the system were incorporated into a system dynamics model to test scenarios of changed water use. Of river water diverted into an earthen irrigation canal system, some was consumed by crop evapotranspiration (7.4%), the rest returned to the fiver as surface return flow (59.3%) and shallow groundwater return flow that originated as seepage from canals (12.1%) and fields (21.2%). The modeled simulations showed that the coupled surface water irrigation system and shallow aquifer act together to store water underground and then release it to the river, effectively retransmitting river flow until later in the year. Water use conversion to nonirrigation purposes and reduced seepage from canals and fields will likely result in higher spring runoff and lower fall and winter river flow. DOI: 10.1061/(ASCE)IR.1943-4774.0000265 CE Database subject headings: Aquifers; Hydrologic models; Hydrogeology; Irrigation systems; Surface water; Groundwater; Groundwater recharge; Rio Grande. Author keywords: River-aquifer interaction; Hydrology; Hydrologic models; Hydrogeology; Irrigation systems; Surface water; Groundwater; Groundwater recharge; Rio Grande.

Recent amendments to the Safe Drinking Water Act emphasize efforts toward safeguarding our nation's water supplies against attack and contamination. Specifically, the Public Health Security and Bioterrorism Preparedness and Response Act of 2002 established requirements for each community water system serving more than 3,300 people to conduct an assessment of the vulnerability of its system to a terrorist attack or other intentional acts. Integral to evaluating system vulnerability is the threat assessment, which in the process by which the credibility of a threat is quantified. Unfortunately, full probabilistic assessment in generally not feasible, since there in insufficient experience and/or data to quantify the associated probabilities. For this reason, an alternative approach is proposed predicated on Marker latent effects (MLE) modeling, which provides a framework for quantifying imprecise subjective metrics through possibilistic or fuzzy mathematics. Here, the MLE approach is introduced and demonstrated within the context of water supply system threat assessment. DOI: 10.1061/(ASCE)0733-9496(2005)131:3(218) CE Database subject headings: Risk management: Risk analysis: Water distribution: Water quality: Potable water: Accidents.

Seasonal runoff from montane uplands is crucial for plant growth in agricultural communities of northern New Mexico. These communities typically employ traditional irrigation systems, called acequias, which rely mainly upon spring snowmelt runoff for irrigation. The trend of the past few decades is an increase in temperature, reduced snow pack, and earlier runoff from snowmelt across much of the western United States. In order to predict the potential impacts of changes in future climate a system dynamics model was constructed to simulate the surface water supplies in a montane upland watershed of a small irrigated community in northern New Mexico through the rest of the 21st century. End‐term simulations of representative concentration pathways (RCP) 4.5 and 8.5 suggest that runoff during the months of April to August could be reduced by 22% and 56%, respectively. End‐term simulations also displayed a shift in the beginning and peak of snowmelt runoff by up to one month earlier than current conditions. Results suggest that rising temperatures will drive reduced runoff in irrigation season and earlier snowmelt runoff in the dry season towards the end of the 21st century. Modeled results suggest that climate change leads to runoff scheme shift and increased frequency of drought; due to the uncontemporaneous of irrigation season and runoff scheme, water shortage will increase. Potential impacts of climate change scenarios and mitigation strategies should be further investigated to ensure the resilience of traditional agricultural communities in New Mexico and similar regions. [ABSTRACT FROM AUTHOR]

Managing water resources in a complex adaptive natural–human system is a challenge due to the difficulty of modeling human behavior under uncertain risk perception. The interaction between human-engineered systems and natural processes needs to be modeled explicitly with an approach that can quantify the influence of incomplete/ambiguous information on decision-making processes. In this study, we two-way coupled an agent-based model (ABM) with a river-routing and reservoir management model (RiverWare) to address this challenge. The human decision-making processes is described in the ABM using Bayesian inference (BI) mapping joined with a cost–loss (CL) model (BC-ABM). Incorporating BI mapping into an ABM allows an agent's psychological thinking process to be specified by a cognitive map between decisions and relevant preceding factors that could affect decision-making. A risk perception parameter is used in the BI mapping to represent an agent's belief on the preceding factors. Integration of the CL model addresses an agent's behavior caused by changing socioeconomic conditions. We use the San Juan River basin in New Mexico, USA, to demonstrate the utility of this method. The calibrated BC-ABM–RiverWare model is shown to capture the dynamics of historical irrigated area and streamflow changes. The results suggest that the proposed BC-ABM framework provides an improved representation of human decision-making processes compared to conventional rule-based ABMs that do not take risk perception into account. Future studies will focus on modifying the BI mapping to consider direct agents' interactions, up-front cost of agent's decision, and upscaling the watershed ABM to the regional scale. [ABSTRACT FROM AUTHOR]

Managing water resources in a complex adaptive natural-human system is subject to a challenging task due to the difficulty of modeling human behavior and decision uncertainty. The interaction between human-engineered systems and natural processes needs to be modeled explicitly, and a formal approach is required to characterize human decision-making processes and quantify the associated uncertainty caused by incomplete/ambiguous information. In this study, we "two-way" coupled an agent-based model (ABM) with a river-routing and reservoir management model (RiverWare) while ABM uses a bottom-up approach that allows individual decision makers to be defined as agents - each able to make their own decisions based on their objectives and confidence in the acquired information. The human decision-making processes is described in the ABM using Bayesian Inference (BI) mapping joined with a Cost-Loss (CL) model (BC-ABM). Incorporating BI mapping into an ABM allows an agent's internal (psychological) thinking process to be specified by a cognitive map between decisions and relevant preceding factors that could affect decision-making. The associated decision uncertainty is characterized by a risk perception parameter in the BI mapping representing an agent's belief on the preceding factors. Integration of the CL model addresses an agent's behavior caused by changing socioeconomic conditions. We use the San Juan River Basin in New Mexico, USA to demonstrate the utility of this method. The calibrated BC-ABM-RiverWare model is shown to capture the dynamics of historical irrigated area and streamflow changes. The results suggest that the proposed BC-ABM framework provides an improved representation of human decision-making processes compared to conventional rule-based ABMs that does not take uncertainties into account. Future studies will focus on modifying the BI mapping to consider direct agents' interactions, up-front cost, joint human and natural uncertainty evaluation, and upscaling the watershed ABM to the regional scale. [ABSTRACT FROM AUTHOR]

Agriculture-based irrigation communities of northern New Mexico have survived for centuries despite the arid environment in which they reside. These irrigation communities are threatened by regional population growth, urbanization, a changing demographic profile, economic development, climate change, and other factors. Within this context, we investigated the extent to which community resource management practices centering on shared resources (e.g., water for agricultural in the floodplains and grazing resources in the uplands) and mutualism (i.e., shared responsibility of local residents to maintaining traditional irrigation policies and upholding cultural and spiritual observances) embedded within the community structure influence acequia function. We used a system dynamics modeling approach as an interdisciplinary platform to integrate these systems, specifically the relationship between community structure and resource management. In this paper we describe the background and context of acequia communities in northern New Mexico and the challenges they face. We formulate a Dynamic Hypothesis capturing the endogenous feedbacks driving acequia community vitality. Development of the model centered on major stock-and-flow components, including linkages for hydrology, ecology, community, and economics. Calibration metrics were used for model evaluation, including statistical correlation of observed and predicted values and Theil inequality statistics. Results indicated that the model reproduced trends exhibited by the observed system. Sensitivity analyses of socio-cultural processes identified absentee decisions, cumulative income effect on time in agriculture, and land use preference due to time allocation, community demographic effect, effect of employment on participation, and farm size effect as key determinants of system behavior and response. Sensitivity analyses of biophysical parameters revealed that several key parameters (e.g., acres per animal unit or percentage of normal acequia ditch seepage) which created less variable system responses but which utilized similar pathways to that of the socio-cultural processes (e.g., socio-cultural or physical parameter change → agricultural profit → time in spent in agriculture → effect on socio-cultural or physical processes). These processes also linked through acequia mutualism to create the greatest variability in system outputs compared to the remainder of tests. Results also point to the important role of community mutualism in sustaining linkages between natural and human systems that increase resilience to stressors. Future work will explore scenario development and testing, integration with upland and downstream models, and comparative analyses between acequia communities with distinct social and landscape characteristics. [ABSTRACT FROM AUTHOR]

This article represents the second report by an ASCE Task Committee “Infrastructure Impacts of Landscape-driven Weather Change” under the ASCE Watershed Management Technical Committee and the ASCE Hydroclimate Technical Committee. Herein, the ‘infrastructure impacts” are referred to as infrastructure-sensitive changes in weather and climate patterns (extremes and non-extremes) that are modulated, among other factors, by changes in landscape, land use and land cover change. In this first report, the article argued for explicitly considering the well-established feedbacks triggered by infrastructure systems to the land-atmosphere system via landscape change. In this report by the ASCE Task Committee (TC), we present the results of this ASCE TC’s survey of a cross section of experienced water managers using a set of carefully crafted questions. These questions covered water resources management, infrastructure resiliency and recommendations for inclusion in education and curriculum. We describe here the specifics of the survey and the results obtained in the form of statistical averages on the ‘perception’ of these managers. Finally, we discuss what these ‘perception’ averages may indicate to the ASCE TC and community as a whole for stewardship of the civil engineering profession. The survey and the responses gathered are not exhaustive nor do they represent the ASCE-endorsed viewpoint. However, the survey provides a critical first step to developing the framework of a research and education plan for ASCE. Given the Water Resources Reform and Development Act passed in 2014, we must now take into account the perceived concerns of the water management community. [ABSTRACT FROM AUTHOR]

This article represents the first report by an ASCE Task Committee "Infrastructure Impacts of Landscape-driven Weather Change" under the ASCE Watershed Management Technical Committee and the ASCE Hydroclimate Technical Committee. In this first of a series of reports, it argues for explicitly considering the well-established feedbacks triggered by infrastructure systems to the land-atmosphere system through landscape changes. A definition for Infrastructure Resilience (IR) at the intersection of extreme weather and climate is also proposed for the engineering community. By providing a broader range of views and issues than what is currently in the front view of engineering practice, more robust approaches can be achieved by the engineering community by affording a greater number of scenarios in its decision making related to infrastructure design, operations and management. Although the article does not strive to seek consensus on any particular view or recommend a particular design/operations strategy for improving resilience, the issues requiring further discussions are addressed. For example, it is not entirely clear at this stage how best to impact engineering practice directly through the research that appears on land-atmosphere feedbacks triggered by infrastructure systems. Some examples related to adjusting design metrics as wholly new (atmospheric model-based) or modified current practices have appeared in recent literature. Performing a survey of actual water managers in the various water infrastructure units (such as U.S. Army Corps of Engineers district offices) would be beneficial for the engineering community. Moving forward, a key focus for the engineering community should be to understand the predictive uncertainty of changes to extreme weather and climate through integrated forcings of landscape change and planetary warming, and the implications of this uncertainty on infrastructure design and operations. [ABSTRACT FROM AUTHOR]

In complex coupled natural-human systems (CNH), multitype networks link social, environmental, and economic systems with flows of matter, energy, information, and value. Embedded Resource Accounting (ERA) is a systems analysis framework that includes the indirect connections of a multitype CNH network. ERA is conditioned on perceived system boundaries, which may vary according to the accountant's point of view. Both direct and indirect impacts are implicit whenever two subnetworks interact in such a system; the ratio of two subnetworks' impacts is the embedded intensity. For trade in the services of water, this is understood as the indirect component of a water footprint, and as 'virtual water' trade. ERA is a generalization of input-output, footprint, and substance flow methods, and is a type of life cycle analysis. This paper presents results for the water and electrical energy system in the western U.S. This system is dominated by California, which outsources the majority of its water footprint of electrical energy. Electricity trade increases total water consumption for electricity production in the western U.S. by 15% and shifts water use to water-stressed Colorado River Basin States. A systemic underaccounting for water footprints occurs because state-level processes discount a portion of the water footprint occurring outside of the state boundary. [ABSTRACT FROM AUTHOR]

A significant fraction of our nation's electricity use goes to lift, convey, and treat water, while the resulting expenditures on electricity represent a key budgetary consideration for water service providers. To improve understanding of the electricity-for-water interdependency, electricity used in providing water services is mapped at the regional, state and county level for the 17-conterminous states in the Western U.S. This study is unique in estimating electricity use for large-scale conveyance and agricultural pumping as well as mapping these electricity uses along with that for drinking and wastewater services at a state and county level. Results indicate that drinking and wastewater account for roughly 2% of total West-wide electricity use, while an additional 1.2% is consumed by large-scale conveyance projects and 2.6% is consumed by agricultural pumping. The percent of electricity used for water services varies strongly by state with some as high as 34%, while other states expend less than 1%. Every county in the West uses some electricity for water services; however, there is a large disparity in use ranging from 10 MWh/yr to 5.8 TWh/yr. These results support long-term transmission planning in the Western U.S. by characterizing an important component of the electric load. [ABSTRACT FROM AUTHOR]

In New Mexico, increasing demand for water, combined with limited supplies and periodic drought, is placing additional stress on traditional acequia communities. Research on the hydrology of acequia agriculture in northern New Mexico has been carried out in three communities and their associated watersheds and irrigated valleys. Critical to the effort has been the participation of the acequias and individual farmers, ranchers, and other community member stakeholders. Participation in hydrology research included assistance in altering flows in acequias, and access to private property and wells, critical to obtain ground and surface water measurements. Further research that integrated hydrologic data with ecosystem, land-use, economics, and sociocultural data, via development of a system dynamics model, required community member participation through surveys, interviews, and workshops to develop, calibrate and refine the model. [ABSTRACT FROM AUTHOR]

Hydrologic connectivity can be important when assessing the role of water availability and distribution in sustaining different natural processes and human activities in a given landscape. We present a study that served as one of five case studies for an interdisciplinary modeling course. The main objectives of the study presented are: 1) to characterize the hydrologic connectivity between the uplands and the irrigated valley and; 2) to set the foundations for understanding the connections between hydrology and complementary disciplines of ecology, rangeland management, and system dynamics modeling in a semiarid watershed in the southwestern United States. Study results show a strong hydrologic connectivity between surface and groundwater in the lower agricultural valley that follows a seasonal pattern, driven primarily by irrigation contributions to the shallow aquifer. The interdisciplinary modeling team assigned to this study was able to use data from it and outside sources to create a working model that addressed these interconnections and highlighted the study value of concurrent consideration of multiple components of linked hydrologic, economic, ecological, and social systems. [ABSTRACT FROM AUTHOR]

Irrigation percolation can be an important source of shallow aquifer replenishment in arid regions of the southwestern United States. Aquifer recharge derived from irrigation percolation can be more significant in fluvial valleys overlying shallow aquifers, where highly permeable soils allow rapid water infiltration and aquifer replenishment. This study used data from various irrigation experiments and data at the piezometric level to assess the irrigation percolation effects on the recharge of a shallow aquifer in an agricultural valley of northern New Mexico. The water balance method (WBM) and the water table fluctuation method (WTFM) were used to estimate aquifer recharge at the field scale () and the WTFM was used to determine recharge at the entire valley scale (). Also, the temporal and spatial distribution of aquifer response to irrigation percolation and canal seepage inputs was characterized. The results showed that for separate irrigation events at the field scale, aquifer recharge values ranged from 0 to 369 mm when using the WBM and from 0 to 230 mm when using the WTFM. For the cumulative irrigation season at the valley scale, recharge ranged from 1,044 to . A relatively rapid water table response with sharp water table rises and declines was observed in all but dryland location wells in response to canal seepage and irrigation percolation inputs. The results of this study add to the understanding of the mechanisms of shallow aquifer recharge and the interactions between surface water and groundwater in a floodplain agricultural valley of northern New Mexico. [ABSTRACT FROM AUTHOR]

Carbon capture and sequestration (CCS) has important implications relative to future thermoelectric water use. A bounding analysis is performed using past greenhouse gas emission policy proposals and assumes either all effected capacity retires (lower water use bound) or is retrofitted (upper bound). The analysis is performed in the context of recent trends in electric power generation expansion, namely high penetration of natural gas and renewables along with constrained cooling system options. Results indicate thermoelectric freshwater withdrawals nationwide could increase by roughly 1% or decrease by up to 60% relative to 2009 levels, while consumption could increase as much as 21% or decrease as much as 28%. To identify where changes in freshwater use might be problematic at a regional level, electric power production has been mapped onto watersheds with limited water availability (where consumption exceeds 70% of gauged streamflow). Results suggest that between 0.44 and 0.96 Mm³/d of new thermoelectric freshwater consumption could occur in watersheds with limited water availability, while power plant retirements in these watersheds could yield 0.90 to 1.0 Mm³/d of water savings. [ABSTRACT FROM AUTHOR]

Large amounts of water are required for electricity generation, and demand for thermoelectric power is predicted to increase significantly over the next several decades. Of concern, is that nearly half of this new demand is in regions currently subject to fresh water shortages due to over-appropriation, drought, and climatic drivers. This study explores the suitability of using non-traditional sources of water, namely wastewater and brackish ground water for future thermoelectric cooling in 22 continental Electricity Market Module Regions. Both sources pose unique financial, technical, and management challenges, but are widely available and in the majority of instances economically feasible. While neither resource can meet all future demand by thermoelectric generation, when added to the existing water supply and management portfolio, they provide significant augmentation to existing traditional water supplies. [ABSTRACT FROM AUTHOR]

Water scarcity, land use conversion and cultural and ecosystem changes threaten the way of life for traditional irrigation communities of the semi-arid southwestern United States. Traditions are strong, yet potential upheaval is great in these communities that rely on acequia irrigation systems. Acequias are ancient ditch systems brought from the Iberian Peninsula to the New World over 400 years ago; they are simultaneously gravity flow water delivery systems and shared water governance institutions. Acequias have survived periods of drought and external shocks from changing economics, demographics, and resource uses. Now, climate change and urbanization threaten water availability, ecosystem functions, and the acequia communities themselves. Do past adaptive practices hold the key to future sustainability, or are new strategies required? To explore this issue we translated disciplinary understanding into a uniform format of causal loop diagrams to conceptualize the subsystems of the entire acequia-based human-natural system. Four subsystems are identified in this study: hydrology, ecosystem, land use/economics, and sociocultural. Important linkages between subsystems were revealed as well as variables indicating community cohesion (e.g., total irrigated land, intensity of upland grazing, mutualism). Ongoing work will test the conceptualizations with field data and modeling exercises to capture tipping points for non-sustainability and thresholds for sustainable water use and community longevity [ABSTRACT FROM AUTHOR]

In 2005, thermoelectric power accounted for 41% of all freshwater withdrawals and roughly 3% of all consumptive use in the United States. With the demand for electricity projected to increase by 24% by 2035 concerns have been raised as to the availability of water for this growing industry; particularly, as the siting of several new thermoelectric facilities have been challenged on the basis of water supply. To address this concern we estimate the potential impact of water availability on future expansion of the thermoelectric power industry. Specifically, both the extent and location of thermoelectric developments at risk due to limited fresh water supply is estimated for a variety of alternative energy futures that differ according to the assumed mix of fuels utilized in new plant construction. According to the analyzed scenarios water consumption for thermoelectric power generation is projected to increase by 36-43% between 1995 and 2035, with much of this development expected to occur in basins with rapidly growing demands in the nonthermoelectric sectors. To identify where this thermoelectric development might be problematic, projected future thermoelectric production has been mapped onto basins subject to limited water availability. For the purposes of this study, water availability is defined as a local ratio of water demand to physical water supply. Results suggest that 10-19% of all new thermoelectric power production is likely to be sited in watersheds with limited surface and/or groundwater availability. These problematic watersheds are largely located in the West. [ABSTRACT FROM AUTHOR]

In cooperative modeling projects, a group of people work together to develop a model to better understand a complex system and explore consequences of various ???what if??? scenarios. This report describes a case study from New Mexico in which representatives from diverse organizations and institutions employed system dynamics???based cooperative modeling enhanced by computer-supported cooperative work (CSCW) to design a model that could be used as a tool in making water management decisions. In this case, CSCW was necessitated by the geographically dispersed nature of the participating stakeholders. The case study reflects that, although it is no panacea, cooperative modeling can be a successful way to create a sense of community, even among geographically dispersed citizens and decision makers, to understand contentious and complex water management issues. The purpose of this article is to highlight lessons learned for applying cooperative modeling with CSCW to assist other practitioners and broaden possibilities for improved water management decisions.Environmental Practice 12:316???327 (2010) [ABSTRACT FROM AUTHOR]

Abstract: Using a slab of Massillon Sandstone, laboratory-scale solute tracer experiments were carried out to test numerical simulations using the Advection–Dispersion Equation (ADE). While studies of a similar nature exist, our work differs in that we combine: (1) experimentation in naturally complex geologic media, (2) X-ray absorption imaging to visualize and quantify two-dimensional solute transport, (3) high resolution transport property characterization, with (4) numerical simulation. The simulations use permeability, porosity, and solute concentration measured to sub-centimeter resolution. While bulk breakthrough curve characteristics were adequately matched, large discrepancies exist between the experimental and simulated solute concentration fields. Investigation of potential experimental errors suggests that the failure to fit solute concentration fields may lie in loss of intricate connectivity within the cross-bedded sandstone occurring at scales finer than our property characterization measurements (i.e., sub-centimeter). [Copyright &y& Elsevier]

Equitable allocation of ground water resources is a growing challenge due to both the increasing demand for water and the competing values placed on its use. While scientists can contribute to a technically defensible basis for water resource planning, this framework must be cast in a broader societal and environmental context. Given the complexity and often contentious nature of resource allocation, success requires a process for inclusive and transparent sharing of ideas complemented by tools to structure, quantify, and visualize the collective understanding and data, providing an informed basis of dialogue, exploration, and decision making. Ideally, a process that promotes shared learning leading to cooperative and adaptive planning decisions. While variously named, mediated modeling, group modeling, cooperative modeling, shared vision planning, or computer-mediated collaborative decision making are similar approaches aimed at meeting these objectives. In this paper, we frame “cooperative modeling” in the context of ground water planning and illustrate the process with two brief examples. [ABSTRACT FROM AUTHOR]

Environmental practitioners may find cooperative modeling an effective tool to address complex environmental management needs. The method involves convening a multidisciplinary team to collaboratively construct a system dynamics model. Advances in computational tools have made this technique increasingly effective because the process and the product allow individuals to better understand the complexity inherent in the system being studied. The authors describe four cooperative modeling projects and document some of the ‘lessons learned’ from these experiences. Two of these projects were largely academic and team members were all professionals who agreed to work together to build a model. The other two teams were convened to contribute to water management processes. One of these emanated from a regional plan. fling exercise and the team included professionals and volunteers from the public. The final project team presented includes professionals, members of the public, and government agency personnel. Like any multidisciplinary effort, the teams encountered communication challenges. The overarching lessons derived from these efforts are that teams can never pay too much attention to group dynamics and that the proximity to a ‘real’ management decision does influence the cooperative modeling process. Recommendations to others embarking on a cooperative modeling effort include reviewing the literature regarding previous projects; establishing clear guidelines for team interaction early in the project; and remaining flexible, to allow the project to evolve. [ABSTRACT FROM AUTHOR]

Time domain reflectometry (TDR) operates by propagating a radar frequency electromagnetic pulse down a transmission line while monitoring the reflected signal. As the electromagnetic pulse propagates along the transmission line, it is subject to impedance by the dielectric properties of the media along the transmission line (e.g., air, water, and sediment), reflection at dielectric discontinuities (e.g., air-water or water-sediment interface), and attenuation by electrically conductive materials (e.g., salts and clays). Taken together, these characteristics provide a basis for integrated stream monitoring, specifically, concurrent measurement of stream stage, channel profile, and aqueous conductivity. Requisite for such application is a means of extracting the desired stream parameters from measured TDR traces. Analysis is complicated by the fact that interface location and aqueous conductivity vary concurrently and multiple interfaces may be present at any time. For this reason a physically based multisection model employing the S11 scatter function and Debeye parameters for dielectric dispersion and loss is used to analyze acquired TDR traces. Here we explore the capability of this multisection modeling approach for interpreting TDR data acquired from complex environments, such as encountered in stream monitoring. A series of laboratory tank experiments was performed in which the depth of water, depth of sediment, and conductivity were varied systematically. Comparisons between modeled and independently measured data indicate that TDR measurements can be made with an accuracy of ±3.4 × 10−3 m for sensing the location of an air-water or water-sediment interface and ±7.4% of actual for the aqueous conductivity. [ABSTRACT FROM AUTHOR]

What is the relationship between the visual attributes of a rock sample and its permeability, and how might such information be used in aquifer/reservoir characterization? We investigated these questions by way of three meter-scale blocks of rock, two sandstones, and one volcanic tuff. Each rock exhibits visual and permeability patterns that differ in geometry, intensity, and scale. Using a gas minipermeameter, hundreds to thousands of permeability values were collected on grids at centimeter-scale resolution from each block face and compared to the digital visual image of the same face. We found no significant direct correlation between the permeability measurements and any objective textural measure drawn from the corresponding digital images, despite the obvious resemblance of the permeability maps and visual images. Hypothesizing that the human eye relies on spatial correlation to synthesize information, we calculated and compared semivariograms for both the maps and the images. Semivariogram shape, anisotropy ratio, and principal axes orientation were consistent for the maps and images of each rock but different between rocks. To explore this similarity further, we compared discrete features appearing in map/image pairs, using a difference of Gaussian edge filter to segment (i.e., delineate) the spatial features. The filter consistently colocated visually sharp features, such as sedimentological bounding surfaces, in both the map and the image. Additionally, cumulative distribution functions characterizing the size, shape, and orientation of the segmented features were statistically indistinguishable between a permeability map and its corresponding visual image but statistically different between rocks. These results suggest that it may not always be possible to use visual images (photographs or scans) of outcrops to directly map permeability, even with a training set of punctual permeability data. In particular, defining such relations may be difficult where the scales of analysis and/or intensity of heterogeneity are limited (e.g., within a given facies) as is the case here. Where direct mapping is not possible, these results suggest that visual images can still be used to delineate spatial permeability patterns, especially to locate boundaries where sharp permeability contrasts occur. Other surrogate measurements of permeability, in particular the various geophysical methods, may exhibit similar behavior. [ABSTRACT FROM AUTHOR]