Posts Tagged ‘water use’

2007-9 Drought in Georgia

Thursday, March 1st, 2012

April 2012 article (Early View):The 2007-2009 Drought in Athens, Georgia, United States: A Climatological Analysis and an Assessment of Future Water Availability,” by Pete Campana, John Knox, Andrew Grundstein, and John Dowd.

This case study reports how population increases, combined with a lack of water conservation, led to severe water shortages in the Athens, Georgia region during late 2007. Drought indices and precipitation records indicates that conditions were severe, but not worse than several other drought events. A drought of similar length would be expected to occur approximately every 25 years. Only after per capita usage decreased did water resources last despite continuing drought conditions through 2009.

In all likelihood, the future of water supplies will depend on mitigative and adaptive strategies implemented by the counties that rely on them. Mitigation strategies, such as the water restrictions put in place during 2007, have already proven to be successful at reducing withdrawal levels to a sustainable daily amount. The Athens area was able to avert a crisis partly by taking actions that were in advance of state restrictions on water use. However, Georgia HB 1281 (signed by Gov. Perdue in May 2008) now prevents local governments from getting “ahead of the curve” v. state-level water-use restrictions without application to and approval by the Director of the Georgia EPD on a case-by-case basis, demonstrating “good cause,” and following an EPD-approved process. This is a potentially disastrous top-down directive that reduces the responsiveness of society to drought.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own.]

Bermuda roof catchments

Monday, October 24th, 2011

December 2011 article (early view): “Rain Water Harvesting in Bermuda,” by Mark P. Rowe

Bermuda roof catchment

This article summarizes some of the findings presented in a 2010 Bermuda Government report entitled ‘‘Bermuda’s Water Supply.’’ A major objective of the report was to evaluate the balance of supply vs. demand and assess the adequacy of a system where the principal supply, namely harvested rain water, is not directly measurable.

With a total population of approximately 64,000, Bermuda has one the highest population densities in the world at 11.4 persons per hectare. Every building in Bermuda must have a roof catchment to collect rain water and an associated water storage tank. The average rate at which rain water is harvested at the typical house with four occupants is, however, insufficient to meet average demand. This article describes some of the design aspects of roof catchments and discusses how roof-supplied water may be augmented.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Residential Water Demand

Friday, May 13th, 2011

August 2011 article (Early View): “Residential Demand for Water in the Chicago Metropolitan Area,” by Taro Mieno, and John B. Braden

The specification of the water price variable has been the most controversial issue in water demand estimation studies. This paper take a good look price effects based on eight Chicago-area municipalities which provided water tariff and residential consumption data for 1995-2007.

The quantity of water consumed by households is likely to be affected by many factors including price, demographic characteristics, existing economic policies, climate conditions, water-using technologies, and plumbing codes. Among these factors, the effect of water price, summarized in the price elasticity of water demand, is especially valuable because it is one of the few factors over which water managers have direct control. Price elasticity is defined as the ratio of the percentage change in quantity used to a percentage change in price:

where Q is quantity and P is price.

There are lots of details in the findings, too many to be covered here. Higher income municipalities in Northeastern Illinois appear to be less responsive to changes in water price, which implies that the use of pricing for water conservation can raise equity issues. Increasing prices in summer is a particularly effective way to constrain peak water use and, thus, needs for investments in additional infrastructure and water supply.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Water Conservation Strategies

Thursday, May 12th, 2011

August 2011 article (Early View): “The Impacts of Water Conservation Strategies on Water Use: Four Case Studies,” by Yushiou Tsai, Sara Cohen, and Richard M. Vogel.

In coordination with with four communities in the Ipswich watershed, four water conservation projects were designed to simultaneously meet immediate municipal needs and demonstrate innovative water conservation strategies that could be evaluated with real-world data. The four projects are (1) installation of weather-sensitive irrigation controller switches (WSICS) at residences and at municipal athletic fields, (2) installation of rainwater harvesting systems at residences, (3) town-administered programs to provide home indoor water use audits and fixture retrofit kits and rebates for low-water-demand toilets and washing machines, and (4) soil amendments to improve moisture retention and reduce water demand at a municipal athletic field. Statistical hypothesis tests combined with con- trolled water conservation experiments were used to evaluate water savings.

So what worked best? (1) The WSICS appeared to reduce the variability of water use among residential participants, most notably by causing a reduction in water use of the highest historical water users. (2) Annual volumes of rainwater used were small compared with domestic water use, and reductions in domestic water use as a result of substitution with rainwater could not be dierned amidst the background fluctuations in domestic water use. (3) Nonstatistically significant savings of this group appeared to result from the small sample size and large variation in water savings among the participants. (4) The addition of a moisture and nutrient-retaining additive, zeolite, to the soil of a ball field resulted in healthy turf with less water applied than to an adjacent control field. For details and qualifications, read the paper!

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Water Use Data

Friday, April 29th, 2011

While in Baltimore, I had a chance to catch up with Susan Hutson and talk about the USGS Water-Use Program. In any water-supply study, you’d think the most elemental question would be, “How much water is being used?” Few of us realize how difficult it can be to come by this data.

Problem is, one rarely can go out and measure water use; data typically have to be provided by others or estimated by various methods. Public water utilities can provide information on domestic and commercial use — if metered — but their customer categories follow no consistent definition. Private domestic wells rarely are metered, so use must be based upon housing or population characteristics. Irrigation use is even harder to estimate, especially if supplied from groundwater. I don’t think we appreciate the skill required to make reasonably accurate estimates of water consumption that can be compared consistently from year to year.

The United States Geological Survey has a nation-wide program for estimating water use. It’s run on a shoestring, but specialists for each State compile an estimate of water use for each county every 5 years. They’ve been doing this since 1950. Techniques have changed — GIS being the most prominent advance — but every effort is made to keep the numbers comparable, so trends can be evaluated.

It hard to say what the rest of the world does. I am unaware of any other nation that runs a comparable nation-wide program. Individual utilities may know much about their customers, but not much about self-provided water. Also, it is not too unusual for a utility to report as much of half its water “missing,” so how good can estimates be in these circumstances? One must wonder if we are basing plans upon on a house of cards. The skillset developed by USGS for estimating water use needs to become more widely available to the world.

Landscape water conservation

Tuesday, April 26th, 2011

June 2011 article (Early View):Value Landscape Engineering: Identifying Costs, Water Use, Labor, and Impacts to Support Landscape Choice,” by David E. Rosenberg, Kelly Kopp, Heidi A. Kratsch, Larry Rupp, Paul Johnson, and Roger Kjelgren.

Efforts to change landscape water consumption have been limited for several possible reasons. First, property owners often overwater, regardless of landscape composition. Changing irrigation behaviors to meet rather than exceed plant water needs can yield significant water savings. Second, utilities assume that property owners have already decided what kind of landscaping they want and owners want to keep what they currently have. Third, urban landscapes are complex systems. Plant composition, site-specific conditions, and maintenance activities interact in many ways so that it is difficult to determine the effect on water use of changing one or more landscape system components. And fourth, little information is available to property website imageowners about the impacts of changing one or more landscape components on their overall water and energy consumption. Costs, required labor, fertilizer, fuel, pesticide and energy use, carbon dioxide (CO2) and particulate emissions, esthetics, and other attributes may also influence property-owner landscape choices. Further, existing information is dispersed among scientific and university Cooperative Extension sources, vendors, and landscape professionals, and is not organized or synthesized to support decision making by property owners.

To address some of these limitations and support property owner landscape decisions, the authors have developed a spreadsheet model that identifies the costs, required labor, water, fertilizers, pesticides, energy, fuel, carbon emissions, and particulates required for, or generated over, the life of a user-specified landscape. Landscapers, landscape architects, contractors, and owners of residential and commercial properties can use the model to identify costs, required inputs, and impacts for a current landscape, landscape plan, or modifications to them.

This is a pretty neat tool! I tried it out, though my balcony at JAWRA World Editorial Headquarters allows for only theoretical testing. I wouldn’t say it’s simple enough for everyone, but it’s not bad either. Check it out at http://vle.cuwcd.com/ .

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Alaska’s water resources

Wednesday, January 26th, 2011

February 2011 Article:Alaska’s Freshwater Resources: Issues Affecting Local and International Interests,” by Lilian Alessa, Mark Altaweel, Andrew Kliskey, Christopher Bone, William Schnabel, and Kalb Stevenson.

Alaska has lots and lots of water, right? So, no problem? Not if you think about quality in rural villages, the need to protect endangered species, and, of course, climate change.

The authors present the challenges faced by Alaska in the context of a larger global perspective, and briefly explore the relative effects these issues have on local, regional, and global scales. They argue Alaska needs to develop more robust institutions and policies that can alleviate both household concerns and ensure that Alaska plays a significant role in the international freshwater arena for its long-term resilience.

The authors take a broad and thought-provoking view of Alaska’s water, and their remarks about international issues are sure to raise a few eyebrows: “The need to diversify industry coupled with an abundant potable freshwater supply provides the opportunity for Alaska to play a major role in global freshwater issues during the next 50 years.”

I like for JAWRA to give its readers something to think about!

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

Saving Water

Thursday, December 16th, 2010

Jasmine Hall, of Onlineclasses.org, alerted me to their new publication, “101 Way to Conserve Water in College.” Interesting collection of advice.

Some of the entries on landscape watering are right in line with recent JAWRA articles: #39. Connect irrigation systems to weather systems: This prevents watering plants when it’s raining. See my November 19, 2010 posting.

Some tips are simply good personal habits, which will prove very useful if you live or travel in a really water-stressed area like the Middle East. #2. Turn water off when brushing your teeth: And while shaving or even washing your face. and #13. Turn off water while you wash your hair. The latter offers minimal savings in my case. :-)

Others are a little curious: Referring to institutions, #51 Take out some laundry facilities: People will do laundry more often … if the laundry room is convenient. A guy definitely wrote this one!

Finally, here’s my favorite, as it raises all kinds of issues: #11 Don’t use the toilet for arbitrary flushes: Throw cigarette butts and bugs in the trash, instead of sacrificing the 5-7 gallons of water it takes to flush. Wouldn’t quitting be better? I suspect toilets will remain the method of choice for discreet disposal of non-standard smoking materials. The toilet recently proved useful when a county executive in Maryland allegedly had to dispose of some embarrassing large checks when the FBI showed up with a warrant.

Arsenic and old tap water

Monday, December 6th, 2010

December 2010 article:Costs of Arsenic Treatment for Potable Water in California and Comparison to U.S. Environmental Protection Agency Affordability Metrics,” by Elizabeth J. Hilkert Colby, Thomas M. Young, Peter G. Green, and Jeannie L. Darby.

Removing arsenic is expensive — relatively. The median cost of compliance with the revised arsenic MCL for the surveyed systems was $1.95?1,000gallons (2008 dollars), which is 69% of the average cost of delivered tap water in the U.S. in 2008. 15% paid more than the USEPA’s affordability limit for drinking water ($16.06 ? 1,000 gallons). Compliance with the revised arsenic regulation in California can require significant investment, especially for SWS.

This is good information, but you need to place it into perspective: $16 bucks per thousand gallons still is far cheaper than bottled water.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]

School landscape irrigation

Friday, November 19th, 2010

December 2010 article:Implementing Landscape Water Conservation in Public School Institutional Settings: A Case for Situational Problem Solving,” by Douglas C. Kilgren, Joanna Endter-Wada, Roger K. Kjelgren, and Paul G. Johnson

The authors studied irrigated landscape water conservation at public schools in Utah, controlling for type of irrigation and water conservation interventions. Their findings suggest ways for school districts to decide where, when, and how to intervene in promoting water conservation. To me, they seem a good combination of science and common sense.

Water conservation programs targeted at large institutional landscapes like public school grounds are likely to produce water savings mainly because of the size of irrigated acreage. However, water savings might best be realized by focusing resources and education primarily on locations that have historically over irrigated. Locations with high capacity to conserve water can be identified through analysis of water billing data and comparison to ETo-based thresholds that categorize landscape water use as conserving, acceptable, or wasteful. Absent the resources to conduct such analyses, conservation interventions would likely be most effective if they are targeted at schools that fit certain profiles (automated-irrigation systems, smaller grounds, high water pressure, and nine-month calendar) and at schools in certain circumstances (in transition from manual to automated-irrigation systems, experiencing custodian turn-over, exhibiting high water use variability between years). Monitoring water use and being strategic about when as well as where to undertake conservation efforts is important for achieving larger system efficiencies in water use and conservation program administration.

[Please note: I have quoted and paraphrased freely from the article, but the interpretation is my own!]