Water research round-up

This is a collection of links to articles that have been recently published that I find relevant to my work or just interesting from a content or methods perspective.

Intermittent supply-related 

Coulibaly, L., Jakus, P. M., and Keith, J. E. (2014) Modeling water demand when households have multiple sources of water. Water Resources Research (just accepted).
Abstract: A significant portion of the world’s population lives in areas where public water delivery systems are unreliable and/or deliver poor quality water. In response, people have developed important alternatives to publicly supplied water. To date, most water demand research has been based on single-equation models for a single source of water, with very few studies that have examined water demand from two sources of water (where all non-public system water sources have been aggregated into a single demand). This modeling approach leads to two outcomes. First, the demand models do not capture the full range of alternatives so the true economic relationship amongst the alternatives is obscured. Second, and more seriously, economic theory predicts that demand for a good becomes more price-elastic as the number of close substitutes increases. If researchers artificially limit the number of alternatives studied to something less than the true number, the price elasticity estimate may be biased downward. This paper examines water demand in a region with near universal access to piped water, but where system reliability and quality is such that many alternative sources of water exist. In extending the demand analysis to four sources of water we are able to (i) demonstrate why households choose the water sources they do, (ii) provide a richer description of the demand relationships among sources, and (iii) calculate own-price elasticity estimates that are more elastic than those generally found in the literature.
My notes: The study was conducted in the Zarqa Governate of Jordan, where piped water was delivered 41 hours/week and households also rely on tanker trucks, water filled at shops, and bottled water. They found that households chose to consume from sources other than piped water because of limited hours, undesirable water aesthetics , and perceptions of illness.

Venkatachalam, L. (2014) Informal water markets and willingness to pay for water: a case study of the urban poor in Chennai City, India. International Journal of Water Resources Development, 1–12.
Abstract: The present study analyzes the role of informal markets in fulfilling the water requirements of poorer households in Chennai City, India. The results of a survey reveal that a significant number of poor people purchase water from informal markets and that they incur a sizeable expenditure on water purchases; some of these households are also willing to pay additional amounts for improved water supply from public sources. The results suggest that improvements in public water supply would significantly increase the welfare of the poor. The informal markets need to be regulated and monitored so that they can serve the households in a better way.

Water quality in distribution systems 

World Health Organization (2014), Water safety in distribution systems, Geneva.

Chowdhury, S. and Al-Zahrani, M. (2014) Modeling Heterotrophic Bacteria in Plumbing System of Drinking Water. Water Environment Research, 86(6), 504–512.Abstract: This study investigated occurrences of heterotrophic (HPC) bacteria and developed predictive models for HPC bacteria in plumbing pipes (PP) and hot water tanks (HWT) of two houses in Dhahran (Saudi Arabia). Heterotrophic bacteria in PP and HWT were observed to be 2.4 to 5.3 and 0.4 to 5.9 times the HPC bacteria in water distribution system (WDS), respectively. Three linear, one nonlinear, and one neural network models were investigated to predict HPC bacteria in PP and HWT. Significant factors for bacteria regrowth in PP and HWT were identified through numerical and graphical techniques. The R2 values of the models varied between 0.57 and 0.96, indicating moderate to excellent predictive ability for HPC bacteria in PP and HWT. The models were found to be statistically significant, which were also validated using additional data. These models can be used to predict HPC bacteria regrowth from WDS to PP and HWT, and could help to predict exposure and risks.

Water Quality Monitoring

Jung, A.-V., Le Cann, P., Roig, B., Thomas, O., Baurès, E., and Thomas, M.-F. (2014) Microbial Contamination Detection in Water Resources: Interest of Current Optical Methods, Trends and Needs in the Context of Climate Change. International Journal of Environmental Research and Public Health, 11(4), 4292–4310.
Abstract: Microbial pollution in aquatic environments is one of the crucial issues with regard to the sanitary state of water bodies used for drinking water supply, recreational activities and harvesting seafood due to a potential contamination by pathogenic bacteria, protozoa or viruses. To address this risk, microbial contamination monitoring is usually assessed by turbidity measurements performed at drinking water plants. Some recent studies have shown significant correlations of microbial contamination with the risk of endemic gastroenteresis. However the relevance of turbidimetry may be limited since the presence of colloids in water creates interferences with the nephelometric response. Thus there is a need for a more relevant, simple and fast indicator for microbial contamination detection in water, especially in the perspective of climate change with the increase of heavy rainfall events. This review focuses on the one hand on sources, fate and behavior of microorganisms in water and factors influencing pathogens’ presence, transportation and mobilization, and on the second hand, on the existing optical methods used for monitoring microbiological risks. Finally, this paper proposes new ways of research.

Modeling – Water-borne diseases and environmental drivers

Finger, F., Knox, A., Bertuzzo, E., Mari, L., Bompangue, D., Gatto, M., et al. (2014) Cholera in the Lake Kivu region (DRC): Integrating remote sensing and spatially explicit epidemiological modeling. Water Resources Research (just accepted).
Abstract: Mathematical models of cholera dynamics can not only help in identifying environmental drivers and processes that influence disease transmission, but may also represent valuable tools for the prediction of the epidemiological patterns in time and space as well as for the allocation of health care resources. Cholera outbreaks have been reported in the Democratic Republic of the Congo since the 1970s. They have been ravaging the shore of Lake Kivu in the east of the country repeatedly during the last decades. Here we employ a spatially explicit, inhomogeneous Markov chain model to describe cholera incidence in eight health zones on the shore of the lake. Remotely sensed datasets of chlorophyll concentration in the lake, precipitation and indices of global climate anomalies are used as environmental drivers in addition to baseline seasonality. The effect of human mobility is also modelled mechanistically. We test several models on a multi-year dataset of reported cholera cases. The best fourteen models, accounting for different environmental drivers, and selected using the Akaike information criterion, are formally compared via proper cross-validation. Among these, the one accounting for seasonality, El Niñno Southern Oscillation, precipitation and human mobility outperforms the others in cross-validation. Some drivers (such as human mobility and rainfall) are retained only by a few models, possibly indicating that the mechanisms through which they influence cholera dynamics in the area will have to be investigated further.

Integrated Watershed Management

Nerkar, S. S., Tamhankar, A. J., Khedkar, S. U., and Lundborg, C. S. (2014) Quality of Water and Antibiotic Resistance of Escherichia coli from Water Sources of Hilly Tribal Villages with and without Integrated Watershed Management—A One Year Prospective Study. International Journal of Environmental Research and Public Health, 11(6), 6156–6170.
Abstract: In many hilly tribal areas of the world, water scarcity is a major problem and diarrhoea is common. Poor quality of water also affects the environment. An integrated watershed management programme (IWMP) aims to increase availability of water and to improve life conditions. Globally, there is a lack of information on water contamination, occurrence of diarrhoea and antibiotic resistance, a serious global concern, in relation to IWMP in hilly tribal areas. Therefore, a prospective observational study was conducted during 2011–2012 in six villages in a hilly tribal belt of India, three with and three without implementation of an IWMP, to explore quality of water, diarrhoeal cases in the community and antibiotic resistance of Escherichia coli from water sources. The results showed that physico-chemical quality of water was within limits of safe consumption in all samples. The odds of coliform contamination in water samples was 2.3 times higher in non-watershed management villages (NWMV) compared to integrated watershed management villages (IWMV) (95% CI 0.8–6.45, p = 0.081). The number of diarrhoeal cases (18/663 vs. 42/639, p < 0.05) was lower in IWMV as compared to NWMV. Overall E. coli isolates showed high susceptibility to antibiotics. Resistance to a wider range of antibiotics was observed in NWMV.

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Adventures in data collection: What causes contamination in intermittent piped water supplies?

In this paper, Mechanisms Affecting Water Quality in an Intermittent Piped Water Supply, we use my hard-earned data – collected by hanging out on the side of roads in Hubli and Dharwad, watching over a pressure sensor and a physico-chemical sensor (see Fig. 1 below) and running to collect grab samples for entire days at a time – to understand how water becomes contaminated in an intermittent supply and watch it happen.

Papers don’t convey some of the interesting stories behind the research, so this space is a good opportunity to do so. Like that time that I had these sensors in the bottom of a 3 foot deep hole that had been dug so I could hook them up directly to the pipe. When the water turned on (for which I sat there waiting for a few hours), I noticed water seeping in through sides of the pit –  there was a leak somewhere nearby and water started filling, filling, filling – not that slowly – the pit. Not wanting to damage the equipment, I got down in the pit, borrowed a bucket from a sympathetic nearby house, and started bailing the water out. After about 30 minutes of exhausting bailing, a group of school girls crowds around, with one asking, “Auntie, auntie, what are you doing?”. I responded with “I am moving water,” and the girl says “oh” and walks away. I keep bailing. Check out the Supplementary Info (ungated!) Fig. 3 part f. See all that time the pressure was >0 psi? I was there in the pit bailing out water.

Below I’m including some photos of the data collection efforts – and the adventures that come with it.

Image

Fig 1. One of the more calm setups. Except for the street dogs early in the morning and the literature-eating cow (see below).

Kumpel, E. and Nelson, K. L. (2014) Mechanisms affecting water quality in an intermittent piped water supply. Environmental Science & Technology, 48(5), 2766–2775.

ABSTRACT: Drinking water distribution systems throughout the world supply water intermittently, leaving pipes without pressure between supply cycles. Understanding the multiple mechanisms that affect contamination in these intermittent water supplies (IWS) can be used to develop strategies to improve water quality. To study these effects, we tested water quality in an IWS system with infrequent and short water delivery periods in Hubli-Dharwad, India. We continuously measured pressure and physicochemical parameters and periodically collected grab samples to test for total coliform and E. coli throughout supply cycles at 11 sites. When the supply was first turned on, water with elevated turbidity and high concentrations of indicator bacteria was flushed out of pipes. At low pressures (<10 psi), elevated indicator bacteria were frequently detected even when there was a chlorine residual, suggesting persistent contamination had occurred through intrusion or backflow. At pressures between 10 and 17 psi, evidence of periodic contamination suggested that transient intrusion, backflow, release of particulates, or sloughing of biofilms from pipe walls had occurred. Few total coliform and no E. coli were detected when water was delivered with a chlorine residual and at pressures >17 psi.

Cow in the doorway

I thought this cow that came up next to where I was sitting to get its morning breakfast of chapati from the neighbors was awesome until…

 

eaten paper

It decided chapati wasn’t enough and it wanted some knowledge too and took a chunk out of the paper I was reading. Sargaonkar, A., Nema, S., Gupta, A., and Sengupta, A. (2010) Risk assessment study for water supply network using GIS. Journal of Water Supply: Research and Technology—AQUA, 59(5), 355, this cow found your paper delectable.

 

24×7 Water news in India – April 2012

Reportedly daily protests in Khandwa, near Bhopal, against the privatization part of a 24×7 plan. Dissent in Mangalore by various groups. Also in Visakhapatnam over plans to close down public taps.  Positive article in the Economic Times by the  former secretary of the ministry of urban development regarding the potential of PPPs for 24×7 water supply across India.

Surat preparing for 24×7, reportedly planning on providing to recently resettled urban poor first.

Professor Asit Biswas stated, during a visit to Nagpur, that 24×7 water a good solution for “cheap” and “good quality” water (quotes from the ToI article, not necessarily from him).  The article also includes more details of the 24×7 project by OCWL in Nagpur, including 30% of pipes to be replaced and supply to 3 lakh (300,000) households.  Prof. Biswas also stated huge distribution system losses – citing 60% in Delhi – as the main factor for lack of 24×7.

ToI points out that this time of year in which more consumers in Mumbai complain of water quality problems (the newspaper looked at complaint records, a shockingly low 167 over 3 months in all of Mumbai).   BMC states that it is unlikely they will need to cut water supplies this summer because of high enough levels in the source lakes. Hindustan Times reports that the areas from Mulund to Vikhroli are getting 24×7, with it extending to eastern suburbs as of last week and, soon to Ghatkopar and Kurla.  I’m still surprised that I’ve seen so few details on how this was implemented (normalization of connections, installation of meters, repairing pipes, etc), but perhaps I just haven’t looked hard enough.

24×7 Water in India – March news

New 24×7 proposals and discussions (with rather rapid timetables!): Panaji says 24×7 for them in 3 years once water treatment plants are completed (but no specific 24×7 management plan), while Guwahati says four years (with a pilot in East Guwahati with ADB and Japanese bank funding assistance), and a small mention of a planned pilot of 24×7 in ThaneVisakhapatnam cleared the 24×7 project to be completed in two years.

Expansion of 24×7 planned in the budget of Karnataka that was recently approved which included 1700 crore to expand Hubli-Dharwad, Belgaum, and Gulbarga’s 24×7 and 146 crore for Mangalore’s.  Nagpur’s JNNURM project for 24×7 is reportedly 68% done for the pilot areas and 1% done for the city (I’m not sure what that percent quite means).

The dry season is heating up with reports of reduced water availability around the country.  In Pune, construction sites will no longer get water, but more dramatically a newspaper in Mangalore announced that the nearby dam had only 9 day’s supply of water. According to this article, it suggests that some of the problems with achieving 24×7 in Mangalore have been due to a reduced budget which did not allow for rehabilitation of old pipelines, leading to high leakage rates especially in transmission lines.

Housing societies in Ahmedabad have apparently taken it upon themselves to install water meters to encourage conservation – reportedly using less water and reducing down their electricity bill.  Debate still ongoing about installing meters in Pune.

Also, in attempting to start collecting leakage rates in various cities:

24×7 Water in India – Feb/March 2012 news

Indian Express has an article on Amravati, Maharashtra, wich reportedly provides 24×7 water to its 40,000 residents (covering 4 of the 16 city zones). The article also mentions what seems to be potential 24×7 in Badlapur, east of Mumbai, in a partnership between Maharashtra Jeevan Pradhikaran and the Malaysian Ranhill Utilities.  The controversy continues in Mysore, and investigations planned in Nagpur regarding tariffs and 24×7 project there (the visit was supposed to happen March 1 but apparently has been postponed).  Apparently Mulund in Mumbai now has 24×7 or feasibility plans (I can’t tell from the article if the feasibility plans have been done or if there actually is 24×7 supply now – does anyone know? It seems like from the DNA article that it’s not actually implemented yet), and is talking about extending it to Ghatkopar, Vikhroli, and Bhandup.

Mangalore is starting to close public taps, illegal connections, and meter connections in preparation for 24×7, and Pune is looking at installing meters,  costing the plan right now, and conducting a water audit. ToI reminds us that in Nov of last year, the civi standing committee approved the 24×7 water supply scheme with the Italian consultant Studio Galli Ingegneria to make the plans.

Revived 24×7 proposal in Visakhapatnam (in AP), and dissent in Bhopal over a potential 24×7 scheme.

Other related news, ToI notes that Nagpur is starting to try to collect arrears – estimated to be 70 crore ($14 million USD), noting that each year cost recovery has decreased – by keeping offices open longer.

There have been some great articles in the ToI and India Express this month about water management in cities in India.  ToI looks at the water crisis in Bangalore using examples from several places in the city. Electronic City, who say they even are having trouble with obtaining supplies from tankers and purchased borewell water and are asking consumers to cut back. Residents in Sarjapur (where I usually stay when I’m in Bangalore!), completely depend on tankers (since there is no BWSSB pipelines here) who have been changing their prices, and another residential area, Whitefield, have 24×7 if they are in gated communities (not clear where that comes from) but use water tankers outside of the gated communities.  Interestingly, an area of the city called Austin Town is expected not to have a big problem because of the presence of defense establishments nearby who harvest rainwater (I assume this means that many people in Austin Town are using borewell water).

I’m excited to see several reporters this month discussing water scarcity concerns in more detail than the usual ‘lack of sufficient monsoon rains’ that is too often seen at this time of year.  ToI has a great article on Pune, where the utility has been cutting the water supply this summer and officials cite leakage and lost water as the reason.  There are reportedly 11.5 TMC of water set aside for Pune, and 14TMC area drawn from the reservoirs, however, officials cite losses and management problems as the reason for cuts, with various finger-pointing as to whose responsibility it is to reduce UAW (reportedly at 40%). The article goes on to talk about the role of water theft, sewage treatment, quotas from the reservoirs, and rainwater harvesting and their options and problems for mitigating the problems, and a review of some of the past measures put forth and shelved in the past (the reporter did a great job giving the problem of urban water scarcity the complex analysis it requires, far above many other articles I’ve seen in Indian newspapers – definitely check it out).  Indian express has a good (if brief) interview with PMC Water Chief, where he discussing uncontrolled growth of the city and planned recycling of wastewater and reduction of leaks.  Bangalore reports surface water depletion, particularly in small lakes, as development has changed land patterns and affected drainage. The Deccan Herald mentions that some people blame water scarcity on new developments. ToI reports problems in the Pench I4 project in Nagpur, which is supposed to increase capacity by 115 MLD by increasing pumping and water treatment plant capacity, and also potential threats to the current supply due to a new dam in AP – though it also mentions 50% UAW which would, if reduced, effectively increase the supply of water.

PS – Happy AWWA Fix a Leak Week!