Too much, too less, too bad? - Adapting to climate change impacts on water quantity and quality in the drylands of Maharashtra, India

The state of Maharashtra is with around 112 million people the second most populous state in India. Over half of its population lives in rural areas, facing problems related to water scarcity and pollution. More than 30% of the state falls under the rain shadow area. The drought prone areas are affected by rainfall deficits, dry spells and erratic distribution of rainfall. Groundwater resources are often over-exploited and cities, farmers and industry compete for the available water. The project "Too much, too less, too bad? - Adapting to climate change impacts on water quantity and quality in the drylands of Maharashtra, India" studied the impacts of future climate change, population growth and urbanization on water demand and availability as well as water quality. The study region were Pune and Satara province, which face high rainfalls in the west in the mountain range Western Ghats and low rainfalls in the east. Climate modelling results under consideration of climate change show an increase of mean temperature of 2,4 oC for the coast and 2,6 oC for the dry inland until 2080. Monsoon rainfalls are predicted to increase by 20- 30%, but the overall rainfall pattern becomes more erratic. This means a higher risk for flooding and diminished agricultural production, as plants can suffer from water scarcity in their growing phase. Sampling of water sources showed a seasonal trend of higher levels of faecal indicator bacteria in surface water and open wells during monsoon season, whereas it was not observable in bore wells fed by deep groundwater. This trend was also reflected in diarrhea incidence data. The current water treatment system takes this into account as households during monsoon are provided with chlorine-solution for free to treat their water prior to consumption. After heavy rainfall events we found with a time-delay of 2-3 days increased levels of faecal coliform bacteria in open wells and surface waters. As rainfall becomes more erratic a higher frequency of such episodes can be expected in a changing climate. In the typical water supply systems in our study region water is pumped from the water source (borewell, open well) to a village storage tank. Either in the storage tank or directly in the open well the water is commonly treated with chlorine for disinfection purposes before it is distributed to households or to community taps by gravitation pressure. The responsibility for chlorination lies with a ?waterman?, who is appointed by the village government. On average households are supplied with water between 0.5 and 2 hours every or every second day, which makes water storage necessary. Due to inappropriate water handling or insufficient hygiene practices water can become contaminated during storage. However, water quality can also be improved by household water treatment and storage interventions. These interventions include for example regular cleaning of storage vessels, filtration treatment for removal of particles and boiling or chlorination to reduce microbiological contamination. In our study we found both in our study water sources with low bacteriological pollution levels and higher levels in household storages. Fortunately we more often found the opposite - a decrease in the concentration of coliforms from the water source to the households. By following the water quality from the source to the point of consumption, we could show that the reliability of the current treatment system is weak i.e. disinfection routines at village level rely on a single person, household treatment is not performed in all households. Rural households are highly vulnerable to failures in water supply, as this forces them to use water sources of inferior quality. Assessment of current and future (2021) water demand was performed by means of population interpolation, analysis of urbanization-trends and estimation of agricultural and industrial demand. Agriculture is and will be the largest water consumer. Assuming an average rural and urban diet, currently 35% of the water used in agriculture is used to satisfy national food needs, whereas 65% is used for cash-crops. In comparison with other nations India has a low water-efficiency (crops produced per m3 water), so there is a large saving potential. While the Indian Government aims for a minimum water supply of 135 litres per capita and day (lpcd), respondents in our household survey reported an average drinking water requirement of 11 lpcd and 54 lpcd for domestic purposes in the dry season (slightly lower values the rest of the year). An urban citizen uses approximately 20% more water than a rural dweller, so continuous urbanization will contribute to an increase in water consumption. Rising temperatures will increase water demand, more erratic rainfalls will increase the risk that plants will dwarf during their growth period, so it is therefore recommended to install irrigation, which in turn leads to higher water demand.

Maharashtra is with around 112 million people the second most populous state in India. More than 30 % of the state falls under the rain shadow area. In these drylands precipitation concentrates to monsoon season from June until September. While monsoon ca uses floods, the rest of the year cities and villages, industry and farmers, and the environment compete for the same scarce water and water conflicts arise. Changes in water availability along with increase in temperature could e.g. have profound effect on the productivity of water-intensive crops such as rice and sugarcane. Additionally the region faces problems with drinking water quality. Chemical pollution of groundwater is mainly due to salinity, fluoride and nitrate. Bacteriological pollution in ru ral as well as in urban areas is mainly due to inadequate sanitation. Population growth and urbanization are further aggravating these problems. "Too-India" seeks to predict the impacts of climate change on the hydrological system in the drylands of Mahar ashtra with respect to water availability and quality, assess the subsequent socio-economic consequences for related sectors and livelihoods and propose technical and non-technical adaptation solutions. The project focuses on two case study areas: Pune an d Satara district, where the problems water scarcity, rural-urban water allocation, and poor drinking water quality congregate. Combining regional climate modelling with bacteriological and chemical analyses of water samples, will allow us to predict futu re trends in water availability and quality. These results we will be matched with data about water demand considering vulnerability aspects and water allocation processes, to come up with sustainable technical and non-technical adaptation options, which will be discussed with the stakeholders. The storage of project results in a GIS and the development of a decision support tool, will allow the stakeholders to benefit from the project beyond the project period.