Tag Archives: Water Resources

Majority of European Alpine glacier melt occurred prior to 1875

Sigl, M., Abram, N. J., Gabrieli, J., Jenk, T. M., Osmont, D., and Schwikowski, M.: 19th century glacier retreat in the Alps preceded the emergence of industrial black carbon deposition on high-alpine glaciers, The Cryosphere, 12, 3311-3331, https://doi.org/10.5194/tc-12-3311-2018, 2018.

“Starting around AD1860, many glaciers in the European Alps began to retreat from their maximum mid-19th century terminus positions, thereby visualizing the end of the Little Ice Age in Europe. Radiative forcing by increasing deposition of industrial black carbon to snow has been suggested as the main driver of the abrupt glacier retreats in the Alps. The basis for this hypothesis was model simulations using elemental carbon concentrations at low temporal resolution from two ice cores in the Alps.”

“Our study reveals that in AD1875, the time when rBC ice-core concentrations started to significantly increase, the majority of Alpine glaciers had already experienced more than 80% of their total 19th century length reduction, casting doubt on a leading role for soot in terminating of the Little Ice Age.”

Does watershed protection lower the cost of drinking water treatment?

Price JI, Heberling MT. The Effects of Source Water Quality on Drinking Water Treatment Costs: A Review and Synthesis of Empirical Literature. Ecological Economics 2018 Sep 3;151:195-209. doi: 10.1016/j.ecolecon.2018.04.014.

Watershed protection, and associated in situ water quality improvements, has received considerable attention as a means for mitigating health risks and avoiding expenditures at drinking water treatment plants (DWTPs). This study reviews the literature linking source water quality to DWTP expenditures. For each study, we report information on the modeling approach, data structure, definition of treatment costs and water quality, and statistical methods. We then extract elasticities indicating the percentage change in drinking water treatment costs resulting from a 1% change in water quality. Forty-six elasticities are obtained for various water quality parameters, such as turbidity, total organic carbon (TOC), nitrogen, sediment loading, and phosphorus loading. An additional 29 elasticities are obtained for land use classification (e.g., forest, agricultural, urban), which often proxy source water quality. Findings indicate relatively large ranges in the estimated elasticities of most parameters and land use classifications. However, average elasticities are smaller and ranges typically narrower for studies that incorporated control variables consistent with economic theory in their models. We discuss the implications of these findings for a DWTP’s incentive to engage in source water protection and highlight gaps in the literature.

Global models underestimate decadal water storage trends

Bridget R. Scanlon, Zizhan Zhang, Himanshu Save, Alexander Y. Sun, Hannes Müller Schmied, Ludovicus P. H. van Beek, David N. Wiese, Yoshihide Wada, Di Long, Robert C. Reedy, Laurent Longuevergne, Petra Döll, and Marc F. P. Bierkens. Global models underestimate large decadal declining and rising water storage trends relative to GRACE satellite data. PNAS January 22, 2018. 201704665; https://doi.org/10.1073/pnas.1704665115.

Assessing reliability of global models is critical because of increasing reliance on these models to address past and projected future climate and human stresses on global water resources. Here, we evaluate model reliability based on a comprehensive comparison of decadal trends (2002–2014) in land water storage from seven global models (WGHM, PCR-GLOBWB, GLDAS NOAH, MOSAIC, VIC, CLM, and CLSM) to trends from three Gravity Recovery and Climate Experiment (GRACE) satellite solutions in 186 river basins (∼60% of global land area). Medians of modeled basin water storage trends greatly underestimate GRACE-derived large decreasing (≤−0.5 km3/y) and increasing (≥0.5 km3/y) trends. Decreasing trends from GRACE are mostly related to human use (irrigation) and climate variations, whereas increasing trends reflect climate variations. For example, in the Amazon, GRACE estimates a large increasing trend of ∼43 km3/y, whereas most models estimate decreasing trends (−71 to 11 km3/y). Land water storage trends, summed over all basins, are positive for GRACE (∼71–82 km3/y) but negative for models (−450 to −12 km3/y), contributing opposing trends to global mean sea level change. Impacts of climate forcing on decadal land water storage trends exceed those of modeled human intervention by about a factor of 2. The model-GRACE comparison highlights potential areas of future model development, particularly simulated water storage. The inability of models to capture large decadal water storage trends based on GRACE indicates that model projections of climate and human-induced water storage changes may be underestimated.

Unverifiable Stream Water Quality Models: Believe it or Not!

Islam MMM, Iqbal MS, Leemans R, Hofstra N. Modelling the impact of future socio-economic and climate change scenarios on river microbial water quality. International journal of hygiene and environmental health. 2017 Dec 4. pii: S1438-4639(17)30408-X. doi: 10.1016/j.ijheh.2017.11.006.

Microbial surface water quality is important, as it is related to health risk when the population is exposed through drinking, recreation or consumption of irrigated vegetables. The microbial surface water quality is expected to change with socio-economic development and climate change. This study explores the combined impacts of future socio-economic and climate change scenarios on microbial water quality using a coupled hydrodynamic and water quality model (MIKE21FM-ECOLab). The model was applied to simulate the baseline (2014-2015) and future (2040s and 2090s) faecal indicator bacteria (FIB: E. coli and enterococci) concentrations in the Betna river in Bangladesh. The scenarios comprise changes in socio-economic variables (e.g. population, urbanization, land use, sanitation and sewage treatment) and climate variables (temperature, precipitation and sea-level rise). Scenarios have been developed building on the most recent Shared Socio-economic Pathways: SSP1 and SSP3 and Representative Concentration Pathways: RCP4.5 and RCP8.5 in a matrix. An uncontrolled future results in a deterioration of the microbial water quality (+75% by the 2090s) due to socio-economic changes, such as higher population growth, and changes in rainfall patterns. However, microbial water quality improves under a sustainable scenario with improved sewage treatment (-98% by the 2090s). Contaminant loads were more influenced by changes in socio-economic factors than by climatic change. To our knowledge, this is the first study that combines climate change and socio-economic development scenarios to simulate the future microbial water quality of a river. This approach can also be used to assess future consequences for health risks.

Assessment of the Municipal Water Cycle in China

Tao Wang, Shuming Liu, Xuepeng Qian, Toshiyuki Shimizu, Sébastien M.R. Dente, Seiji Hashimoto, Jun Nakajima. Assessment of the municipal water cycle in China. Science of The Total Environment Volumes 607–608, 31 December 2017, Pages 761-770.

Water produced from municipal utilities accounts for nearly 10% of the sum water demand in China. The municipal water cycle that integrates processes of urban water supply, water use, sewage treatment, and water reclamation has been assessed for 655 cities across nine drainage areas in mainland China in 2012. These cities in total extracted 55 km3 raw water for municipal use from surface waterbodies and ground aquifers, approximate to the countrywide freshwater extraction of Russia or Italy. After purification and transmission, 45 km3 water was distributed to industrial, service, and domestic users. 36 km3 of post-use sewage was collected and environmentally safely treated; merely 3.2 km3 of the treated water was reclaimed. Driven by increasing urbanization, the municipal water demand in cities of China may grow 70% by 2030. The Hai River and the Huai River basins, which harbor 137 cities and occupy a majority of the densely populated North China Plain, are most exposed to physical water scarcity. The municipal water abstraction in these cities can remain constant by promoting demand-side and process conservation in the next two decades. Interbasin transfer and unconventional sources will provide municipal water double than the cities’ need. Whereas the urban water security can be technically enhanced, the challenges are to better improve water use efficiency and mitigate economic and environmental costs of the municipal system.

Anderson Dam (California) is Seismically Unstable

“The water district that manages Silicon Valley’s 235-foot-high earthen Anderson Dam, which holds 29 billion gallons of water, has acknowledged that the dam’s embankments are seismically unstable and could catastrophically liquefy in a major earthquake.” click here

Water Transfer Rule upheld by 2nd Circuit Court of Appeals

The U.S. Court of Appeals for the 2nd Circuit in a 2-1 ruling reversed a lower court finding EPA’s Clean Water Act (CWA) rule exempting the transfer of water from one basin to another from discharge permits is a reasonable interpretation of the law, and therefore should be upheld under the agency judicial deference doctrine known as Chevron. The full ruling is here. An excerpt is below:

Before: SACK, CHIN, and CARNEY, Circuit Judges.

In 2008, the United States Environmental Protection Agency promulgated the ʺWater Transfers Rule,ʺ which formalized the Agencyʹs longstanding position that water transfers are not subject to regulation under the National Pollutant Discharge Elimination System permitting program established decades ago by the Clean Water Act.  Shortly thereafter, the plaintiffs, a consortium of environmental conservation and sporting organizations and several state, provincial, and tribal governments, challenged the Water Transfers Rule by bringing suit in the United States District Court for the Southern District of New York against the Agency and its Administrator.  After a variety of persons and entities on both sides of the issue intervened, the district court (Kenneth M. Karas, Judge) granted summary judgment for the plaintiffs on the ground that the Water Transfers Rule, although entitled to deferential review under the two‐step framework established by Chevron, U.S.A., Inc. v. Natural Resources Defense Council, Inc., 467 U.S. 837 (1984), could not survive judicial scrutiny because it was based on an unreasonable interpretation of the Clean Water Act.  The district court accordingly vacated the Water Transfers Rule and remanded it to the Agency for further assessment.  We conclude that the Water Transfers Rule is based on a reasonable interpretation of the Clean Water Act and therefore entitled to Chevron deference.  Accordingly, the judgment of the district court is REVERSED.