More Like this

1. Addressing the contribution of indirect potable reuse to inland freshwater salinization

   https://doi.org/10.1038/s41893-021-00713-7  

   Bhide, Shantanu V. ; Grant, Stanley B. ; Parker, Emily A. ; Rippy, Megan A. ; Godrej, Adil N. ; Kaushal, Sujay ; Prelewicz, Greg ; Saji, Niffy ; Curtis, Shannon ; Vikesland, Peter ; et al ( April 2021 , Nature Sustainability)

   null (Ed.)

   Inland freshwater salinity is rising worldwide, a phenomenon called the freshwater salinization syndrome (FSS). We investigate a potential conflict between managing the FSS and indirect potable reuse, the practice of augmenting water supplies through the addition of highly treated wastewater (reclaimed water) to surface waters and groundwaters. From time-series data collected over 25 years, we quantify the contributions of three salinity sources—a water reclamation facility and two rapidly urbanizing watersheds—to the rising concentration of sodium (a major ion associated with the FSS) in a regionally important drinking-water reservoir in the Mid-Atlantic United States. Sodium mass loading to the reservoir is primarily from watershed runoff during wet weather and reclaimed water during dry weather. Across all timescales evaluated, sodium concentration in the reclaimed water is higher than in outflow from the two watersheds. Sodium in reclaimed water originates from chemicals added during wastewater treatment, industrial and commercial discharges, human excretion and down-drain disposal of drinking water and sodium-rich household products. Thus, numerous opportunities exist to reduce the contribution of indirect potable reuse to sodium pollution at this site, and the FSS more generally. These efforts will require deliberative engagement with a diverse community of watershed stakeholders and careful consideration of the local political, social and environmental context. 

   more » « less
2. Adapting to extreme events: small drinking water system manager perspectives on the 2012–2016 California Drought

   https://doi.org/10.1007/s10584-021-03305-8  

   Klasic, Meghan ; Fencl, Amanda ; Ekstrom, Julia A. ; Ford, Amanda ( February 2022 , Climatic Change)

   Under a changing climate, droughts are projected to increase in frequency and duration in the Southwestern USA. Between 2012 and 2016, California experienced one of the region’s worst droughts, with record high temperatures and low snowpack, runoff, and precipitation. This study documents small drinking water system managers’ experiences during the 2012–2016 Drought. We contribute to research on water system drought resilience by elevating small drinking water system manager perspectives and expertise. We are especially focused on small systems that are not reliant on imports from state or federal water projects. A mixed-method approach ensures each data collection period informs the next to gather statewide perspectives and experiences of managers.

   Based on an analysis of drinking water manager reflections, the types of impacts, responses, and barriers differed based on both system size and water source portfolio. Common disadvantages that hinder small drinking water systems’ drought resilience and, similarly, climate adaptation include staff and administrative capacity; the financial burden of promoting water conservation over revenue compounded by onerous reporting and funding support programs; consumer awareness challenges; and challenges to consolidation from both local political differences and physical limitations. Systems that built technical, managerial, or financial capacity prior to the Drought were at an advantage over systems that lacked this capacity. In the long term, we found a dearth of adaptation planning among small water systems. Documentation of experiences from the 2012–2016 Drought can inform future planning for droughts and more broadly highlight needs for climate adaptation.

    

   more » « less
3. The Intersection of Wastewater Treatment Plants and Threatened and Endangered Species in California, USA Watersheds

   https://doi.org/10.1029/2022WR033976  

   Cassady, Anna ; Anderson, Kurt E. ; Schwabe, Kurt A. ; Regan, Helen M. ( August 2023 , Water Resources Research)

   A changing climate and often unregulated water extractions have exposed over 2 billion people to water stress worldwide. While water managers have explored a portfolio of options to reduce this stress, supply augmentation through reuse of treated municipal wastewater is becoming increasingly attractive. Wastewater treatment plants protect water quality and prevent sewage from contaminating waterways. Increasingly, this resource is utilized for numerous human (e.g., irrigation, drinking water, groundwater recharge) and conservation (e.g., stream and river recharge) needs in water stressed regions. To understand the role treated municipal wastewater plays in impacting conservation objectives we identified the intersection of wastewater treatment plant locations and occurrences of threatened and endangered (T&E) species in California and compared the permitted contribution of effluent to baseflow quantities of the receiving waterbody to assess the degree to which changes in effluent could affect instream waterbodies. We found a positive correlation between the presence of treatment plants and T&E species in California watersheds—a quarter of species have 100% of their range in watersheds with at least one treatment plant. This correlation is greatest for species associated with terraces and riparian habitat, followed by aquatic habitat and aquatic emergent vegetation. One‐third of watersheds in our analysis can receive most of their cumulative watershed baseflow from effluent and are characterized by dense urbanization or agriculture. Our analysis demonstrates that the fates of T&E species and effluent are interconnected in ways important for water policy, suggesting that species conservation goals should be considered when making decisions about effluent reuse.

    

   more » « less
4. Influence of foliar traits, watershed physiography, and nutrient subsidies on stream water quality in the upper midwestern United States

   https://doi.org/10.3389/fenvs.2022.974206  

   Singh, Aditya ; Townsend, Philip A ( March 2023 , Frontiers in Environmental Science)

   The relationship between nutrient cycling and water quality in mixed-use ecosystems is driven by interactions among biotic and abiotic processes. However, the underlying processes cannot always be directly observed or modeled at broad spatial scales. Numerous empirical studies have employed land use patterns, variations in watershed physiography or disturbance regimes to characterize nutrient export from mixed-use watersheds, but simultaneously disentangling the effects of such factors remains challenging and few models directly incorporate vegetation biochemistry. Here we use structural equation models (SEMs) to assess the relative influence of foliar chemical traits (derived from imaging spectroscopy), watershed physiography, and human land use on the water quality (summer baseflow nitrate-N and soluble reactive phosphorus concentration) in watersheds across the Upper Midwestern United States. We use an SEM to link water quality (stream nitrate-nitrogen and dissolved phosphorus) to foliar retention (AVIRIS-Classic derived foliar traits related to recalcitrance), watershed retention (wetland proportion, MODIS Tasseled Cap Wetness), runoff (agricultural and urban land use), and watershed leakiness (AVIRIS-Classic foliar nitrogen, nitrogen deposition). The SEMs confirmed that variables associated with foliar retention derived from imaging spectroscopy are negatively related to watershed leakiness (standardized path coefficient = −0.892) and positively to watershed retention (standardized path coefficient = 0.705), with features related to watershed retention and runoff exerting the strongest controls on water quality (standardized path coefficients of −0.270 and 0.331 respectively). Comparing forested and agricultural watersheds, we found significantly increased importance of foliar retention to watershed leakiness in forests compared to agriculture (standardized coefficients of −1.004 and −0.764 respectively), with measures of watershed retention more important to runoff and water quality in agricultural watersheds. The results illustrate the capacity of imaging spectroscopy to provide measures of foliar traits that influence nutrient cycling in watersheds. Ultimately, the results may help focus development and restoration policies towards building more resilient landscapes that take into consideration associations among functional traits of vegetation, physiography and climate.

    

   more » « less
5. Riverine dissolved organic matter transformations increase with watershed area, water residence time, and Damköhler numbers in nested watersheds

   https://doi.org/10.1007/s10533-024-01169-5  

   Ryan, Kevin_A ; Garayburu-Caruso, Vanessa_A ; Crump, Byron_C ; Bambakidis, Ted ; Raymond, Peter_A ; Liu, Shaoda ; Stegen, James_C ( August 2024 , Biogeochemistry)

   Quantifying the relative influence of factors and processes controlling riverine ecosystem function is essential to predicting future conditions under global change. Dissolved organic matter (DOM) is a fundamental component of riverine ecosystems that fuels microbial food webs, influences nutrient and light availability, and represents a significant carbon flux globally. The heterogeneous nature of DOM molecular composition and its propensity for interaction (i.e., functional diversity) can characterize riverine ecosystem function across spatiotemporal scales. To investigate fundamental drivers of DOM diversity, we collected seasonal water samples from 42 nested locations within five watersheds spanning multiple watershed sizes (~ 5 to 30,000 km²) across the United States. Patterns in DOM molecular richness, aromaticity, relative abundance of N-containing formulas, and putative biochemical transformations derived from high-resolution mass spectrometry were assessed across gradients of explanatory variables associated with watershed characteristics (e.g., watershed area, water residence time, land cover). We found that putative biochemical transformations were more strongly related to explanatory variables across watersheds than common bulk DOM parameters and that watershed area, surface water residence time and derived Damköhler numbers representing DOM reactivity timescales were strong predictors of DOM diversity. The data also indicate that catchment-specific land cover factors can significantly influence DOM diversity in diverging directions. Overall, the results highlight the importance of considering water residence time and land cover when interpreting longitudinal patterns in DOM chemistry and the continued challenge of identifying generalizable drivers that are transferable across watershed and regional scales for application in Earth system models. This work also introduces a Findable Accessible Interoperable Reusable (FAIR) dataset (> 300 samples) to the community for future syntheses.

    

   more » « less