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Groundwater depletion threatens global freshwater resources, necessitating urgent water management and policies to meet current and future needs. However, existing data-intensive approaches to assessments do not fully account for the complex human, climate, and water interactions within transboundary groundwater systems. Here, we present the design of and findings from a pilot participatory modeling workshop aiming to advance understanding of the hydrologic–human–climate feedback loops underpinning groundwater systems. Using participatory modeling tools and methods from the system dynamics tradition, we captured the mental models of researchers from water, social, data, and systems sciences. A total of 54 feedback loops were identified, demonstrating the potential of this methodology to adequately capture the complexity of groundwater systems. Based on the workshop outcomes, as an illustrative example, we discuss the value of participatory system modeling as a conceptualization tool, bridging perspectives across disciplinary silos. We further discuss how outcomes may inform future research on existing knowledge gaps around groundwater issues, and in doing so, advance interdisciplinary, use-inspired research for water decision-making more broadly. [ABSTRACT FROM AUTHOR]

There is a need to support applied, community‐relevant hydrologic research within changing climate, population, and socioeconomic conditions to better inform water policy and management. We hypothesized that providing a rural agricultural community in a semiarid valley with the necessary monitoring tool to meet local water management needs would increase adaptive capacity within the context of long‐term drought. Through a community science approach, researchers installed a telemetry monitoring system at participating acequia irrigation diversions that remotely sent water data to a web interface every 15 min. Two surveys distributed before and after web interface access targeted seven adaptive capacity indicators. After the first season of improved data accessibility, the following adaptive capacity indicators significantly increased: information diversity, cognitive social capital, leadership, and proactivity. Rather than focusing on the water savings aspect of real‐time monitoring, this paper summarizes a novel water resources study that assessed the social impact of real‐time irrigation water delivery monitoring on adaptive capacity. This study suggests that bridging the gap between community need and hydrologic research through community science, sociologic analysis, and stakeholder engagement provides significant benefits for communities facing water management challenges, further supporting problem‐driven water resources research. [ABSTRACT FROM AUTHOR]

We studied the roles of traditional irrigation systems called acequias in supporting riparian habitat in terms of riparian tree planting success. We planted Populus deltoides wislizenii (Rio Grande cottonwood) pole cuttings at locations close to and far from surface water: 1, 2, and 3 m from the edge of an acequia, within 100 m from the river that supplies water to the acequia, and in the middle (lengthwise) of a 500-m-long, 115-m-wide, fallow field between the acequia and the river. The poles were planted at deep and shallow depths. We measured survival and growth at each plot and planting depth after the 2008 and 2009 growing seasons. We hypothesized that the poles planted near the acequia would survive and grow similarly to poles planted near the river. Acequia-related seepage created localized areas where riparian plantings had survival rates >80%. Poles planted by the acequia and river had higher survival rates (>80%) than those in the fallow field (<50%). The deeper plantings led to, on average, 50% more growth than the shallow plantings in terms of height gain, leaf area, number of new shoots, and basal diameter gain. Results from this study show that acequias successfully support cottonwood pole plantings. Estudiamos el papel de los sistemas de riego tradicionales llamados acequias apoyando el hábitat ribereño en términos del éxito en el establecimiento de árboles plantados. Plantamos esquejes (palos) de Populus deltoides wislizenii (álamo del río Grande) en lugares cercanos y alejados de la superficie del agua: 1, 2 y 3 m de distancia de la orilla de una acequia, dentro de 100 metros del río que alimenta la acequia, y en medio (a lo largo) de un campo no cultivado de 500 metros de longitud y 115 m de ancho, ubicado entre la acequia y el río. Los palos fueron plantados profundos y no profundos en la tierra. Evaluamos la sobrevivencia y crecimiento en cada lugar y profundidad de la siembra después de la temporada de crecimiento en 2008 and 2009. La hipótesis fue que los palos plantados cerca de la acequia sobrevivirían y crecerían de manera similar a los plantados cerca del río. Las filtraciones de la acequia crearon áreas donde la tasa de supervivencia de la siembra ribereña fue >80%. Los palos plantados cerca de la acequia y del río tuvieron mayores tasas de supervivencia (>80%) que los plantados en el campo no cultivado (<50%). Los palos sembrados más profundos resultaron en un promedio de 50% más de crecimiento que los menos profundos, esto en términos de crecimiento de altura, superficie foliar, número de nuevos brotes, y crecimiento de diámetro basal. Los resultados de este estudio muestran que las acequias promueven exitosamente la siembra de palos de álamo. [ABSTRACT FROM AUTHOR]

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.

The extensive interest in sustainable water management reflects the extent to which the global water landscape has changed in the past twenty years, which is a natural development of changes in water resources and an increase in the level of imbalance between water supply and demand. In this paper, a simulation model based on system dynamics (SD) methodology was developed to aid sustainable water management efforts in a semi-arid region. Six policy scenarios were used to study, analyze, and assess water management trends in the Southeast region of New Mexico, USA. The modeling process included two phases: calibration (2000–2015) and future prediction (2016–2050). Several statistical criteria were applied to assess the developed model performance. The findings revealed that the simulated outputs were in excellent agreement with the historical data, indicating accurate model simulation. The SD model's determination coefficients ranged from 0.9288 to 0.9936 and the index of agreement values ranged from 0.9397 to 0.9958. Findings for the business-as-usual scenario indicated that total water withdrawals and total population will continue to rise, whereas groundwater storage, agricultural consumptive water use, and total consumptive water use will decrease over the simulated period. Sensitivity analysis using Monte Carlo simulation indicated that cultivated irrigated land change is the most influential parameter affecting groundwater storage, water supply storage change (total withdrawals), agricultural consumptive water use, and total consumptive water use. The changes occurring in the agricultural cultivated area had a great influence on controlling the groundwater system. Overall, the results showed that our SD model has been successful in capturing the system's dynamic behavior, and confirmed its capability in modeling water management issues for policy and decision makers under semi-arid conditions. [ABSTRACT FROM AUTHOR]

Quantifying groundwater recharge from irrigation in water-scarce regions is critical for sustainable water management in an era of decreasing surface water deliveries and increasing reliance on groundwater pumping. Through a water balance approach, our study estimated deep percolation (DP) and characterized surface water and groundwater interactions of two flood-irrigated fields in northern New Mexico to evaluate the regional importance of irrigation-related recharge in the context of climate change. DP was estimated for each irrigation event from precipitation, irrigation input, runoff, change in soil water storage, and evapotranspiration data for both fields. Both fields exhibited positive, statistically significant relationships between DP and total water applied (TWA), where one field exhibited positive, statistically significant relationships between DP and groundwater level fluctuation (GWLF) and between GWLF and total water applied. In 2021, total DP on Field 1 was 739 mm, where 68% of irrigation water applied contributed to DP. Field 2′s total DP was 1249 mm, where 81% of irrigation water applied contributed to DP. Results from this study combined with long-term research indicate that the groundwater recharge and flexible management associated with traditional, community-based irrigation systems are the exact benefits needed for appropriate climate change adaptation. [ABSTRACT FROM AUTHOR]

In New Mexico in the arid southwestern United States, groundwater recharge is crucial to sustain groundwater (GW), which is vitally important to life, agriculture, industry, and ecosystems. To better understand the changes in recharge statewide, we explored the changes in groundwater recharge (RE), precipitation (P), surface water inflow (SWin), outflow (SWout), diversions (SWdiv), returns (SWret), and surface water and GW evapotranspiration (SWE and GWET) in five New Mexico counties: Taos, Torrance, Doña Ana, Eddy, and Lea during 1975-2015. The results show that the change-point of RE was in the 1990s, leading to contrasting tendencies in RE before and after the change-point with a decreasing rate during the latter one. There was a significant positive relationship between RE and P for Taos. The highest contribution rate (CR) to RE was SWout for Taos, whereas GWET ranked as the top CR for the other counties. Furthermore, the annual CR of GWET to RE increased significantly in all counties except Lea. The above results reveal that P and surface water flows played the dominant role in impacting RE in northern New Mexico where surface water is the primary local water resources, whereas GWET had the highest and increasingly continuous influence in central and southern New Mexico where the surface water is much less than that in northern New Mexico. This study shows that water budgets are important to identify differences in regional hydrological regimes that affect planning to maintain RE to groundwater. [ABSTRACT FROM AUTHOR]

To test this hypothesis, we can add a forecasting mechanism to the model, e.g. by averaging historical values (Eq. (12)) and then using this average value ( I Q i ) to calculate historical trend of inputs ( I R i ) and estimate "predicted availability" (Eq. (13)): HT ht HT ht Here, I i is the length of history we consider in calculating historical trends, and I i is our forecasting horizon. Commons usage rate (Eq. (6)) is a linear function of capital with I i to be an average rate of commons usage per unit of capital. [Extracted from the article]

Current and predicted drought and population growth challenge the longevity of irrigation systems of northern New Mexico. Irrigation ditches, also known as acequias, draw runoff directly from rivers without use of storage reservoirs, so it is important to understand the effects of changing river flow on irrigation flow. This study sought to examine river‐ditch relationships in an agricultural valley of the region. A first order linear model was used to fit the river‐ditch flow relationship on which daily river flow was the explanatory variable and daily ditch flow the response variable. A strong positive relationship between river and ditch flow was observed for all but one of the ditches. Using a statistical model approach that addressed serial autocorrelation, heteroscedasticity, as well as outlier observations, statistical evidence at 5% significance level was found in all ditches but one. The ditch without a positive relationship was at a downstream location, subject to upstream flow diversion that may have influenced river‐ditch flow relationships. Results from this study can be used to evaluate the potential effects of changing socioeconomic dynamics and climate change projections in the operations of these irrigation systems to better understand and manage their water resources. [ABSTRACT FROM AUTHOR]

Abstract: Currently, there is no agreed upon method for estimating evapotranspiration (ET) across large regions such as the state of New Mexico. Remote sensing methods have potential for providing a solution, but require validation. A comparison between field‐scale ET measurements using a portable chamber ET measurement device and modeled ET using the remote sensing Regional Evapotranspiration Estimation Model (REEM) was performed where the model had not been previously evaluated. Data were collected during the growing season of 2015 in three irrigated agricultural valleys of northern New Mexico in agricultural and nonagricultural settings. No statistically significant difference was observed in agricultural datasets between means of measured (M = 3.7 mm/day, SE = 0.31 mm/day) and modeled (M = 4.0 mm/day, SE = 0.01 mm/day) daily ET; t(17) = −1.50, p = 0.15, α = 0.05. As there was no statistical difference observed between agricultural datasets, results support the use of REEM in irrigated agricultural areas of northern New Mexico. A statistically significant difference was observed in nonagricultural datasets between means of measured (M = 1.7 mm/day, SE = 0.22 mm/day) and modeled (M = 0.0 mm/day, SE = 0.00 mm/day) daily ET; t(9) = 1.79, p = 5.7 × 10−6, α = 0.05. With additional calibrations and air temperature sensors placed outside of agricultural areas, REEM may be suitable for use in nonagricultural areas of northern New Mexico. [ABSTRACT FROM AUTHOR]

Better understanding of surface water (SW) and groundwater (GW) interactions and water balances has become indispensable for water management decisions. This study sought to characterize SW-GW interactions in three crop fields located in three different irrigated valleys in northern New Mexico by (1) estimating deep percolation (DP) below the root zone in flood-irrigated crop fields; and (2) characterizing shallow aquifer response to inputs from DP associated with irrigation. Detailed measurements of irrigation water application, soil water content fluctuations, crop field runoff, and weather data were used in the water budget calculations for each field. Shallow wells were used to monitor groundwater level response to DP inputs. The amount of DP was positively and significantly related to the total amount of irrigation water applied for the Rio Hondo and Alcalde sites, but not for the El Rito site. The average irrigation event DP using data for the complete irrigation season at each of the three sites was 77.0 mm at El Rito, 54.5 mm at Alcalde and 53.1 mm at Rio Hondo. Groundwater level rise compared to pre-irrigation event water levels ranged from 3 to 1870 mm, and was influenced by differences in irrigation practices between sites. Crop evapotranspiration estimates averaged across irrigation events were highest in Rio Hondo (22.9 mm), followed by El Rito (14.4 mm) and Alcalde (10.4 mm). Results from this study indicate there are strong surface water-groundwater connections in traditionally irrigated systems of northern New Mexico, connections that may be employed to better manage groundwater recharge and river flow. [ABSTRACT FROM AUTHOR]

Ecological challenges in western forests continue to place a significant burden on land management practitioners. Increased tree densities since European settlement is arguably the greatest ecological challenge faced by land [...]

Increasing size and severity of wildfires have led to increased interest in managing forests for resiliency to future disturbances. Comparing and contrasting treated versus untreated stands through multiple growing seasons postfire provide an opportunity to understand processes driving responses and can guide management decisions regarding resiliency. In treated and untreated forests, we compared fire effects 2-10 growing seasons following fire on 3 different fires in New Mexico and Arizona. We estimated understory cover, standing crop, fuel loading, and basal area in (1) lop, pile, burn; (2) lop and scatter; (3) harvest and burn; and (4) untreated control stands. Untreated sites had persistent bare soil exposure and less litter cover up to 10 growing seasons after fire. However, there were few differences in standing crop among years and treatments. Falling rampikes contributed to greater coarse woody debris on untreated sites versus treated sites 6 -10 years postfire. However, there were few differences in fine fuel loading among treatments. Proactive management using the full range of silvicultural tools can reduce fire severity and create desired stand conditions, depending on management objectives. [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]

Abstract: While the main objective of many silvicultural treatments in the western US is to reduce fire potential, their effects on overstory regeneration, midstory and herbaceous communities is of importance to land managers. To quantify these effects, we measured overstory regeneration, midstory density by species, herbaceous biomass, species richness and cover in commercial and non-commercial treatments with differing slash prescriptions in dry mixed conifer stands of south central New Mexico. Results indicated that overstory regeneration and shrub density were not significantly affected by treatments, although they did increase at one site which appeared to be more mesic than the others. Herbaceous biomass increased 4 years post-treatment in one non-commercial scatter treatment and 3 years post-treatment in the commercial treatment. Species richness was not affected by any of the treatments. Cover of grasses and forbs remained low in all treatments. Soil cover increased in the commercial treatment; however, it decreased each year following treatment. [Copyright &y& Elsevier]

Abstract: The ability of mechanical fuel reduction treatments to mitigate severe fire behavior in dry mixed conifer forests is of interest to land managers as well as the public. We compared fuel loads and indices of crown fire potential to test treatment effectiveness following commercial and non-commercial treatments with differing slash prescriptions in mixed conifer stands at three sites on the Lincoln National Forest in south central New Mexico. Surface and canopy fuels were measured and used to develop custom fuel models in NEXUS 2.0 to estimate torching and crowning indices. Results indicated herbaceous fuel loads were unchanged compared to controls 2 years post-non-commercial and 1 year post-commercial harvest treatment. Sound 1000-h fuels were greater in the scatter and commercial treatments compared to control treatments. The commercial treatment resulted in stand structure closer to historical conditions. Canopy base height increased in all treatments except in stands previously treated 20–30 years ago. Commercial harvest was the only treatment to reduce canopy bulk density and the potential for active crown fire, with the exception of one pile treatment. Non-commercial pile treatments increased the TI. However, due to the danger of crown fire initiation from adjacent stands, further overstory removal is needed in non-commercial treatments to lower crowning potential. Prescribed fire may be used to increase treatment effectiveness in all overstory removal treatments by decreasing surface fuels. [Copyright &y& Elsevier]

Traditional cultures in arid landscapes of the southwestern United States and northern Mexico developed irrigation systems to irrigate floodplain valleys along streams and rivers. Many of these traditional irrigation systems, referred to as acequias, continue to be used today. Population growth in the region is creating pressures to convert agricultural land and irrigation water to urban and other uses. Unique hydrologic features of the acequia systems suggest that, beyond providing crop irrigation, they may provide additional valuable hydrologic, riparian, and agroecosystem functions worth maintaining. We investigated in detail the seepage and the groundwater response to seepage from a traditional acequia irrigation ditch along the Rio Grande in north-central New Mexico. We found that 16% of ditch flow seeps into the ditch bed and banks. Groundwater levels near the ditch and midway between the ditch and the river rise 1 m or more within three to four weeks following the start of the irrigation season. The elevated groundwater table produced by ditch and field seepage is sustained until late summer when groundwater levels again drop. The seepage that provides this annual groundwater recharge also sustains riparian vegetation along the main ditch and side ditches. In light of our hydrologic analysis, we considered seepage-supported riparian areas and their ecological functions including aquatic habitat, terrestrial habitat, and water quality effects. Ace quia hydrology plays an important role in contributing to an ecologically healthy, agriculturally productive, and community-sustaining floodplain agroecosystem. [ABSTRACT FROM AUTHOR]

Transient storage is a measure of the exchange of main channel flow with subsurface hyporheic flow and surface water dead zones. Hyporheic flow, in which river water enters the channel bed and banks to reemerge downstream, promotes biochemical processes that are important for water quality and aquatic habitat. Previous studies have quantified transient storage and hyporheic flow on small streams but were not specifically developed to identify both of these processes over long reaches of large rivers. We studied transient storage on the eighth-order upper Willamette River, which flows through high- porosity gravel deposits conducive to hyporheic flow. We used main channel dye tracer studies and solute transport modeling to estimate transient storage on nine study reaches in a 26-km-long study area. We also took dye measurements within the transient storage zone to identify transient storage flow paths. We obtained estimates of transient storage exchange coefficient, α s (mean equals 1.6×10−4 s−1), and transient storage to main channel cross-sectional area, A s/ A (mean equal to 0.28), that show that significant amounts of water follow flow paths with 0.2-30 hour transient storage zone residence times. Our dye measurements from the transient storage zone itself showed the occurrence of both subsurface and surface flow paths, confirming that hyporheic flow is an important component of estimated transient storage. We found that the two highest A s/ Aestimates were for reaches that spanned the only length of active main channel in our study area that is unconstrained and where the river can rework large gravel deposits. Much of the natural channel complexity that historically promoted hyporheic flow no longer exists on the upper Willamette River. River management targeting the ecological functions provided by hyporheic flow might best focus on restoring historic hydrogeomorphic processes for creating sites conducive to hyporheic flow. [ABSTRACT FROM AUTHOR]

Transboundary aquifers are critical global water supplies facing unprecedented threats of depletion; existing efforts to assess these resources do not adequately account for the complexities of transboundary human and physical system interactions to the determinant of the impact of assessment outcomes. This study developed a system dynamics model with natural, human, and technical system components for a section of the transboundary Mesilla Basin/Conejos-Médanos aquifer to evaluate the following dynamic hypothesis: how and when information from a transboundary aquifer assessment is reported and perceived, in scenarios where two countries follow identical and different timeframes, dynamically impacts the behaviors of the shared aquifer. Simulation experiments were conducted to quantitatively assess the dynamics of transboundary aquifer assessment information reporting and perception delays. These critical feedbacks have not previously been incorporated practically in simulation and analysis. Simulation results showed that the timing and content of reporting can change the dynamic behavior of natural, human, and technical components of transboundary aquifer systems. This study demonstrates the potential for modeling to assist with prioritization efforts during the data collection and exchange phases to ensure that transboundary aquifer assessments achieve their intended outcomes. [ABSTRACT FROM AUTHOR]

The conventional approach of policy interventions in water management that focus on the portions of the system that directly relate to water often lead to unintended consequences that potentially exacerbate water scarcity issues and present challenges to the future viability of many rural agricultural communities. This paper deploys a system dynamics model to illustrate how expanding the policy space of hydrology models to include socioeconomic feedbacks could address these challenges. In this regard, policies that can potentially mitigate general water scarcity in a region of the American Southwest in southern New Mexico are examined. We selected and tested policies with the potential to diminish water scarcity without compromising the system's economic performance. These policies included supporting choices that reduce or limit the expansion of water-intensive crops, promoting workforce participation, encouraging investment in capital, and regulating land use change processes. The simulation results, after the proposed boundary expansion, unveiled intervention options not commonly exercised by water decision-makers, bolstering the argument that integrated approaches to water research that include socioeconomic feedbacks are crucial for the study of agricultural community resilience. [ABSTRACT FROM AUTHOR]

Quantifying groundwater recharge from irrigation practices of arid regions is necessary for efficient and sustainable groundwater resources management. Recharge is difficult to measure directly, many studies have quantified recharge from agricultural fields as a residual of the soil water balance method (WBM) or by other mathematical models estimating evapotranspiration (ET) and measuring soil moisture, rainfall, and irrigation. ET is often estimated using weather parameters from climate stations that are distant from crops. Flooding of fields is the most common form of irrigation used by farmers in the Mesilla Valley, New Mexico to grow alfalfa, one of the state's major crops. The objectives of this study were to quantify recharge in flood irrigated alfalfa fields in the Mesilla Valley, New Mexico using the WBM and actual ET measurements during the 2017 growing season. The study fields were different sizes, crop ages, and soil textures. Actual ET of alfalfa was measured on the largest field using the eddy covariance − energy budget method and applied to the two other nearby fields as estimated ET. All other WBM parameters were measured at each study site (i.e. soil moisture, rainfall, and applied irrigation). Recharge using ET referenced to grass (ETsz) was then calculated using weather parameters and compared with measured ET. Recharge ranged from 618 to 716 mm with no significant statistical differences between the three alfalfa fields (f-ratio of 0.8876 and a p-value of 0.42 using ANOVA). Recharge to irrigation ratio ranged from 37% to 45%. On-farm irrigation efficiency ranged from 54.86% to 59.94%. When compared to measured ET, ETsz underestimated recharge of alfalfa by 11% in the WBM and overestimated recharge by 6% when a reduction in ETsz during harvest periods are considered. The results show that the measurement of actual ET improved recharge estimates in the alfalfa fields. • Estimates of groundwater recharge can be improved by measuring actual ET. • Using ET referenced to grass in the water balance method underestimates recharge. • Flood irrigating alfalfa contributes to groundwater recharge in the Mesilla Valley, NM. • No significant difference in recharge was observed among studied fields. • Measuring ET captures ET reduction during harvests that are missed when estimated. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the authors discuss various reports within the issue on topics including the development and implementation of a course related to disciplinary modeling, the use size of icecaps and solar radiation variability for mathematical modeling, and the use of interdisciplinary models to address climate and water issues.

Agriculture is the most important sector with regard to water resources management due to its social, economic, hydrological, and environmental aspects, and many scholars and researchers have been driven to investigate the dynamic interrelationships among hydrological, environmental, and socioeconomic factors affecting agriculture. The system dynamics (SD) approach has become widely used because of its merits and benefits as a tool to deal with complex, dynamic problems and systems with many aspects and components that are involved and must be understood to ensure sound decisions regarding water and hydrological systems. Although agricultural water management needs to be studied as a main part of water management, socioeconomic management, and environmental management requiring the use of SD, this review shows that SD is currently used to a limited extent in terms of agricultural water management. This paper sheds light on the studies and investigations on the use of SD in the water sector and highlights the strengths of SD in order to encourage researchers to use this promising method to manage such a vital resource. Accordingly, this review seeks to include a comprehensive and up-to-date survey of existing publications and scholarly papers on the use of SD modeling as an effective technique for dealing with different problems associated with planning, management, and analysis of hydrology and water resources systems. Recent trends in the integration of SD with other modeling systems, such as artificial intelligence systems, are discussed along with the limitations and challenges facing application. This article makes a new contribution by giving a foundation of references and studies for scholars, researchers, and academics which encourages future investigation in employing the SD approach to hydrology and water resources management and planning, especially with agricultural water. [ABSTRACT FROM AUTHOR]

Drylands are susceptible to erosion by wind and water. Thus, the reestablishment of vegetation is a crucial focus of watershed restoration in order to stabilize soils and improve water infiltration. Currently, limited research exists quantifying vegetation responses to rock detention structures (RDS) in the Chihuahuan Desert, and no studies have quantified the effects of RDS paired with seed introduction. Our study area in the Rincon Arroyo Watershed, in southern New Mexico, tested the hypotheses that two types of RDS, micro‐catchments and stone‐lines paired with seeding, support increases in seedling recruitment and vegetation cover compared to untreated controls. This study also tested whether the application of seed to RDS alters plant communities in comparison to controls. One season after seeded RDS were applied, seedling recruitment, cover, and plant community responses were evaluated at treatment and control areas. Seeded stone‐lines showed significantly greater seedling recruitment (2×) and cover (0.3×) than controls (p < 0.05), whereas seeded micro‐catchments showed significantly greater cover (0.3×) than controls (p < 0.05) but did not exhibit significant differences in seedling recruitment compared to controls (p > 0.05). The lack of a significant difference between plant communities at treatment and control areas (p > 0.05) suggests that the addition of seed had little to no effect on plant communities or positive responses in seedling recruitment and cover. These results suggest that stone‐lines and micro‐catchments, alone, can support vegetation establishment in degraded dryland watersheds without the addition of seed. [ABSTRACT FROM AUTHOR]

Drylands today are facing a landscape-scale water storage problem. Throughout the increasingly arid Southwest of the United States, vegetation loss in upland watersheds is leading to floods that scour soils and transport sediment that clogs downstream riparian areas and agricultural infrastructure. The resulting higher flow energies and diminished capacity to infiltrate flood flows are depleting soil water storage across the landscape, negatively impacting agriculture and ecosystems. Land and water managers face challenges to reverse the trends due to the complex interacting social and biogeophysical root causes. Presented here is an integrative system dynamics model that simulates innovative and transformative management scenarios. These scenarios include the natural and hydro-social processes and feedback dynamics critical for achieving long-term mitigation of droughts, flooding, and sediment transport. This model is a component of the Flood Flow Connectivity to the Landscape framework, which integrates spatial and hydrologic process models. Scenarios of support and collaboration for land management innovations are simulated to connect flood flow to the floodplains throughout the watershed to replenish soil storage and shallow groundwater aquifers across regional scales. The results reveal the management policy levers and trade-off balances critical for restoring management and water storage capacity to the system for long-term resilience. [ABSTRACT FROM AUTHOR]

Many agropastoral systems worldwide are supported by important linkages between crop production and rangeland grazing. We explored the connections between smallholder farming and public rangeland grazing in northern New Mexico, USA. We retrieved historical data of livestock inventories, drought, and hay production which we analyzed using either ordinary least squares models, generalized autoregressive conditional heteroscedasticity models (GARCH), or exponential GARCH models. We also conducted a survey of farmers and ranchers (n = 74) of traditional communities in our study area using a mixed methods design. County hay production was the only predictor that explained year-to-year variation in allotment livestock numbers. Allotments that increased livestock numbers tended to have larger base properties (mostly irrigated cropland). Most survey respondents (95%) raised livestock and slightly more than half agreed that livestock provided better financial security than crops. Availability of summer grazing lands and ability to grow or purchase hay to feed livestock during winter were the factors cited least (6% of responses) and most (42%), respectively, as limiting farmers’ ability to increase their herd size. Livestock-raising apparently continues to be critical to the acequia agropastoral economy. Ability to acquire winter feed (hay) appears to regulate the demand for summer grazing on public forested rangelands. [ABSTRACT FROM AUTHOR]

Surface irrigation water percolating below the crop rooting zone is important for groundwater recharge in agricultural areas overlying shallow aquifers. The objective of this study was to characterize water movement through the shallow vadose zone following surface irrigation. Two infiltration plots were installed in each of three predominant local soil types. Plots were instrumented to measure soil water content and shallow groundwater level. Data were used to calculate water infiltration, velocity of propagation of the wetting front, water fluxes, and water level response following irrigation. Results showed a low to moderate infiltration rate (0.001-0.056 m h-1), relatively low levels of propagation of the wetting front (0.13-0.79 m h-1), water flux (0.001-0.13 m h-1), and shallow groundwater response (0.01-0.1 m) in Fruitland sandy loam and Werlog clay loam soils. In the Abiquiu-Peralta soil, however, a higher infiltration rate (0.002-0.124 m h-1), wetting front propagation (0.28-3.75 m h-1), water flux (0.007-0.925 m h-1), and water level response (0.01-0.14 m) were observed. Results from this study helped to improve our understanding of the surface water and shallow groundwater interactions in an irrigated valley in northern New Mexico. The field data set obtained in this study can benefit future model characterization and contribute to extrapolating local results to larger spatial areas. [ABSTRACT FROM AUTHOR]