The Importance of Interflow to Groundwater Recharge in a Snowmelt-Dominated Headwater Basin

American Geophysical Union (AGU) | May 23rd, 2019

Understanding the sensitivity of groundwater generation to climate in a mountain system is complicated by the tight coupling of snow dynamics to vegetation and topogr

Understanding the sensitivity of groundwater generation to climate in a mountain system is complicated by the tight coupling of snow dynamics to vegetation and topography. To address these feedbacks, we combine LiDAR-derived snow observations with an integrated hydrologic model to quantify spatially and temporally distributed water fluxes across varying climate conditions in a Colorado River headwater basin. Results indicate annual groundwater flow is an important and stable source of stream water. However, interflow decreases during drought as a function increased plant water use and the relative fraction of groundwater to streams increases. Seasonal snowmelt and vegetation water use regulate small recharge rates in the lower portions of the basin, but snowmelt transported via interflow from high mountain ridges toward convergent topographic zones define preferential recharge in the upper subalpine. Recharge in this zone appears decoupled from annual climate variability and resilient to drought. 

The importance of system configuration for distributed direct potable water reuse

Nature Portfolio (Springer Nature) | April 27th, 2020

Water and wastewater infrastructure worldwide faces unprecedented demand and supply conflicts that require unconventional solutions. In this study, we develop a novel mod

Water and wastewater infrastructure worldwide faces unprecedented demand and supply conflicts that require unconventional solutions. In this study, we develop a novel modelling framework to assess the environmental and economic implications of a hybrid water supply system that supplements a centralized surface water supply with distributed direct potable reuse (DPR) of municipal wastewater, as a strategy to address such challenges. The model is tested with real water and wastewater systems data from the City of Houston, Texas. Results show that supplementing the conventional centralized water supply with distributed DPR would reduce water age in the drinking-water distribution network and hence improve water quality; properly designed system configurations attain system-wide net energy savings even with the high energy consumption of existing technologies used for advanced treatment of the wastewater. A target energy efficiency for future advanced treatment technologies is identified to achieve net energy saving with all hybrid system configurations. Furthermore, distributed DPR remains financially competitive compared with other unconventional water supply solutions. The modelling framework and associated databases developed in this study serve an important research need for quantitatively characterizing distributed and hybrid water systems, laying the necessary foundation for rational design of integrated urban water systems.

The Influence of Zooplankton Availability on Delta Smelt Condition and Foraging Across Habitat Contexts

Publisher not available | December 19th, 2025

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dep

Strategies for endangered species conservation may have different outcomes depending on the habitat context in which they are implemented. Understanding these context-dependent effects can help optimize and target management efforts. In this analysis, we investigate how environmental and food-web conditions interactively affect condition and foraging of Delta Smelt (Hypomesus transpacificus), an endangered fish endemic to the San Francisco Estuary (the estuary). Food limitation, in terms of pelagic zooplankton availability, is considered a main factor that contributes to the decline in Delta Smelt abundance. Our overarching objective was to examine whether the effect of zooplankton on Delta Smelt depended on habitat context. Specifically, we hypothesized that zooplankton would less positively effect Delta Smelt condition—as measured by hepatosomatic index (HSI)—and foraging success in areas with nearby tidal wetlands, because these adjacent habitats may provide access to prey items from the epibenthos and fringing vegetation. In contrast, in regions with limited proximity to wetlands, we hypothesized that Delta Smelt would rely more on pelagic prey, which would manifest as a more positive effect of zooplankton on body condition and foraging success for Delta Smelt. Using models that accounted for habitat in multiple ways, we found little evidence that zooplankton and habitat interactively influenced Delta Smelt condition or gut fullness. Rather, the influence of zooplankton on HSI and gut fullness was generally positive across habitat contexts. Given the well-documented food limitation in the estuary, promoting the availability of pelagic zooplankton is a rational, albeit complex, management aim. Furthermore, our results suggest that efforts to increase zooplankton would broadly benefit Delta Smelt across a wide range of habitat contexts.

The Innovation Deficit in Urban Water: The Need for an Integrated Perspective on Institutions, Organizations, and Technology

Environmental Engineering Science (Mary Ann Liebert, Inc.) | August 1st, 2013

Interaction between institutional change and technological change poses important constraints on transitions of urban water systems to a state that can meet fut

Interaction between institutional change and technological change poses important constraints on transitions of urban water systems to a state that can meet future needs. Research on urban water and other technology- dependent systems provides insights that are valuable to technology researchers interested in assuring that their efforts will have an impact. In the context of research on institutional change, innovation is the development, application, diffusion, and utilization of new knowledge and technology. This definition is intentionally inclusive: technological innovation will play a key role in reinvention of urban water systems, but is only part of what is necessary. Innovation usually depends on context, such that major changes to infrastructure include not only the technological inventions that drive greater efficiencies and physical transformations of water treatment and delivery systems, but also the political, cultural, social, and economic factors that hinder and enable such changes. On the basis of past and present changes in urban water systems, institutional innovation will be of similar importance to technological innovation in urban water reinvention. To solve current urban water infrastructure challenges, technology-focused researchers need to recognize the intertwined nature of technologies and institutions and the social systems that control change.

The Instream Flow Incremental Methodology: A Primer for IFIM

U.S. Department of the Interior (DOI) | March 1st, 1995

This booklet is a primer on the Instream Flow Incremental Methodology (IFIM). Our objective for this primer is to give you a short but comprehensive introduction to the b

This booklet is a primer on the Instream Flow Incremental Methodology (IFIM). Our objective for this primer is to give you a short but comprehensive introduction to the background, philosophical and ecological underpinnings, individual components, and steps in applying IFIM. As a primer, we have tried to keep it simple. Scientific names and other technical details have been avoided, but the primer includes relevant definitions (with key words or phrases indicated in italics for their first use), summaries of the literature where you may wish to turn for further reading, and explanations to increase your understanding of what IFIM is all about and how it works. The primer should reinforce your growing knowledge and provide the necessary stepping stones into more advanced, certified training in IFIM methods. This primer is divided into five more or less independent sections. The first section reviews the history of instream flow problems in the United States. Reading this section should provide you with an understanding ofwhy IFIM emerged to solve certain complex water management problems and hint at future directions. The second section discusses the choice of instream flow methods and, more importantly, provides a framework for deciding whether IFIM is appropriate for the kind of problems you might be facing. The third section reviews the ecological underpinnings of IFIM from a historical perspective. This section is meant to show you the degree to which IFIM components, or models, represent the essence of the biological systems that we are attempting to understand. It is more detailed than the other sections and meant specifically to be of interest to biologists and ecologists. Section four delves into the broader philosophical, problem-solving approach embodied in IFIM.  This perspective is important because the 'facts' alone rarely dictate good decisions; it is how we employ those facts to resolve instream flow problems in an interdisciplinary decision making arena that is important. The fifth section outlines the logical steps in applying IFIM and the information flow that holds them together. Here you will learn how to navigate through the IFIM process from tentative problem identification to problem resolution.

The Inundation of the Salton Basin by the Colorado River and How It Was Caused

Scientific American | April 14th, 1906

If the Colorado River continues to flow through the channel which it has been occupying during the last six months, the geography of the Southwest must be radically ch

If the Colorado River continues to flow through the channel which it has been occupying during the last six months, the geography of the Southwest must be radically changed, for at the present time but little water from the river reaches the Gulf of California, which until recently has formed its main estuary. Except when the river is in flood, the bulk of the water flows into what is known as the Salton Sink in southern California-a distance of fully 160 miles from the gulf.  The new channel of the Colorado takes a northwesterly course, while the channeI it formerly occupied is nearly south. It is perhaps needless to say that this watercourse is not only one of the most important in the Southwest, but is notable for the immense volume of water which it carries, especially during the flood seasons. But the quantity of detritus which it holds in solution is enormous, and is nearly equal to that carried down by the Mississippi at certain seasons of the year, owing to the topography of the region which drains into it. An idea of the quantity of water carried by the Colorado at different times of the year can be gained, when it is stated that actual measurements indicate a flow ranging as high as 30,000 cubic feet per second. It is estimated that if the silt and other material brought down the river in the course of a year were spread evenly over a given 'surface, it would cover no less than 35,000 acres to a minimum depth of one foot. Consequently, the Colorado is almost as much of a "land maker" as the Mississippi, acting like a gigantic suction dredge in carrying away the material in its vicinity and depositing it upon the lowlands near its mouth and in the Gulf of California.

The irrigation efficiency trap: rational farm-scale decisions can lead to poor hydrologic outcomes at the basin scale

Frontiers in Environmental Science | August 28th, 2023

Agricultural irrigation practices have changed through time as technology has enabled more efficient conveyance and application. In some agricultural regions, irrigation

Agricultural irrigation practices have changed through time as technology has enabled more efficient conveyance and application. In some agricultural regions, irrigation can contribute to incidental aquifer recharge important for groundwater return flows to streams. The Henrys Fork Snake River, Idaho (United States) overlies a portion of the Eastern Snake Plain Aquifer, where irrigated agriculture has occurred for over a century. Using irrigator interviews, aerial and satellite imagery, and statistical streamflow analysis, we document the impact of farm-scale decisions on basin-scale hydrology. Motivated to improve economic efficiency, irrigators began converting from surface to center-pivot sprinkler irrigation in the 1950s, with rapid adoption of center-pivot sprinklers through 2000. Between 1978–2000 and 2001–2022, annual surface-water diversion decreased by 311 Mm3 (23%) and annual return flow to the river decreased by 299 Mm3 over the same period. Some reaches that gained water during 1978–2000 lost water to the aquifer during the later period. We use an interdisciplinary approach to demonstrate how individual farm-scale improvements in irrigation efficiency can cumulatively affect hydrology at the landscape scale and alter groundwater-surface water relationships. Return flows are an important part of basin hydrology in irrigated landscapes and we discuss how managed and incidental aquifer recharge can be implemented to recover return flows to rivers.

The Ives Expedition of 1858

Imperial Irrigation District (IID) | October 1st, 1956

The key role of dry days in changing regional climate and precipitation regimes

Nature Portfolio (Springer Nature) | March 13th, 2014

Future changes in the number of dry days per year can either reinforce or counteract projected increases in daily precipitation intensity as the climate warms. We

Future changes in the number of dry days per year can either reinforce or counteract projected increases in daily precipitation intensity as the climate warms. We analyze climate model projected changes in the number of dry days using 28 coupled global climate models from the Coupled Model Intercomparison Project, version 5 (CMIP5). We find that the Mediterranean Sea region, parts of Central and South America, and western Indonesia could experience up to 30 more dry days per year by the end of this century. We illustrate how changes in the number of dry days and the precipitation intensity on precipitating days combine to produce changes in annual precipitation, and show that over much of the subtropics the change in number of dry days dominates the annual changes in precipitation and accounts for a large part of the change in interannual precipitation variability.

The key role of dry days in changing regional climate and precipitation regimes

Nature Portfolio (Springer Nature) | March 13th, 2014

Future changes in the number of dry days per year can either reinforce or counteract projected increases in daily precipitation intensity as the climate warms. We

Future changes in the number of dry days per year can either reinforce or counteract projected increases in daily precipitation intensity as the climate warms. We analyze climate model projected changes in the number of dry days using 28 coupled global climate models from the Coupled Model Intercomparison Project, version 5 (CMIP5). We find that the Mediterranean Sea region, parts of Central and South America, and western Indonesia could experience up to 30 more dry days per year by the end of this century. We illustrate how changes in the number of dry days and the precipitation intensity on precipitating days combine to produce changes in annual precipitation, and show that over much of the subtropics the change in number of dry days dominates the annual changes in precipitation and accounts for a large part of the change in interannual precipitation variability.