Gopal Krishan Scientist - C National Institute of Hydrology, Roorkee- 247667, Uttarakhand, India D.J. Lapworth, Alan MacDonald, Helen Bonsor BGS, UK *Corresponding E-mail: drgopal.krishan@gmail.com Workshop on Improving freshwater monitoring frameworks and data for research and management 23-25 January, 2018 at Kochi, Kerala NIH, Roorkee
Punjab, Haryana, HP, Uttarakhand, part of Rajasthan, N.Delhi and Western UP What exists?/what do we Know? Ground water quality Northwest India Rudimentary Physico-chemical parameters monitored regularly various centre/state govt. Agencies, acad. institute Pollution levels increased drastically due to anthropogenic factors Water levels decreased Other important parameters concerning trace metals etc., high resolution data are limited and localised on the spatial scale What is lacking?/scope for work A comprehensive assessment of the groundwater Rudimentary and special physicochemical parameters Heavy metals Tracer techniques High resolution monitoring All undertaken in uniform experimental protocol, temporal and spatial scale Insight about special properties of the Groundwater Does these have properties unique to it like CC resilience? If so, does high level extration impact these special properties?
INTRODUCTION (Background to groundwater challenges) Motivation Attempt to answer High abstraction What are the recharge potential? Methodology Case Studies Inferences Recommendations Future work GROUNDWATER Analysis Impact of pollution on special properties Understand overall environmental impact on the GW at present - through all the parameters Recomm endations Scrutinizing the science behind contamination of deep aquifers Water Resource Management
Population growth and prosperity increases demand for food, but is there enough water and energy to sustain this? More than 80% of the water abstracted in Northwest India is used for irrigation The availability of cheap water has been a spring board for agriculture Water in many areas is becoming contaminated (F, As, U) or affected by salinization Increasing irrigation efficiency is not necessarily the answer It has been estimated that total volume of groundwater to be about 30,000 km 3. About 20 times the combined annual flow in the Ganges, Indus and Brahmaputra (1200 km 3 ). However as estimated, 23% of this is saline and 37% affected by arsenic. NIH, Roorkee
Mechanisms of salinity from canal irrigation in the Indus Basin Increased salinity reduces the types of crops that can be grown; declining groundwater levels increases pumping costs, energy requirements and makes shallow wells fail NIH, Roorkee
NIH, Roorkee
Some major groundwater issues in the region 1. Increased Groundwater Abstraction Falling groundwater levels in agricultural areas Tension between agricultural and growing high value urban and industrial users Uncertainty about the security of deeper fresh water reserves Public vs private interests and allocation 2. Water Quality Arsenic, fluoride, salinity, microbial contamination from flooding Contamination from agriculture and poor sanitation Rising salinity levels in groundwater Salinisation problems in irrigated soils NIH, Roorkee
Regional setting Highly abstracted unconsolidated layered alluvial aquifer system Draft typology map of the Indo-Gangetic Basin Criteria: Multi-layered, extensive, thick unconsolidated alluvium aquifer coarse sediment Falling groundwater levels Groundwater salinity at depth Extensive irrigation Surface water groundwater interaction Resilience: +High productivity/storage aquifer +High potential meteoric recharge -High abstraction including some cities -- Significant long-term trends in falling water table - - Saline groundwater at depth O1: To collate historical water level responses to abstraction across a representative catchment O2: To collate new evidence on recharge processes, groundwater quality, groundwater residence times, and connectivity of the layered aquifer systems and surface water by repeated sampling of shallow and deep piezometers using a suite of environmental tracers Q1: Is there evidence from GWL variations of enhanced recharge potential induced by abstraction? NIH, Roorkee Q2: Is there evidence of vertical leakage to depth within the layered alluvial system?
Important Environmental Tracers Stable Isotopes (Recharge sources) Age Dating Techniques (Groundwater Residence time tracers) CFCs & SF6 Noble gases Environmental tritium Inorganic chemistry: e.g. Cl, NO3 and trace elements Others Loggers (water level and conductivity) Water Quality Parameters Arsenic, Uranium Tracer: a substance introduced into a biological organism or other system so that its subsequent distribution may be readily followed from its colour, radioactivity, or other distinctive property
Sampling for CFCs, SF6 and stable isotopes CFCs and SF6 modern groundwater dating tools Sample collection by the bottle-in-can method atmospheric air is excluded during sampling to obtain a representative sample air displacement method for CFCs and SF6 specialist techniques and are not routinely sampled or analysed Analysis (rapid and cost-effective ) CFCs and SF6 are measured by gas chromatography using an electron capture detector (GC- ECD) following cryogenic preconcentration The detection limit for CFC concentrations in water is 0.01 pmol/l, while for SF6 it is 0.1 fmol/l CFC sampling
Sampling for noble gases Noble gases thermometry, i.e. recharge temperature, and excess air assessment atmospheric air is excluded during sampling to obtain a representative sample sealed copper tubes for noble gases are specialist techniques and are not routinely sampled or analysed
Study area Bist Doab, Punjab, India Sampling from paired shallow (<50 mbgl) and deep (>100 mbgl) Pre and post monsoon sampling NIH, Roorkee
Long-term changes in phreatic GW levels Large quantity of data available - CGWB Missing meta data is an issue at many sites e.g. pumped or observation wells? NIH, Roorkee
Long-term changes in groundwater levels Matrix of shallow groundwater security NIH, Roorkee
Groundwater residence time tracer results anthropogenic and natural NIH, Roorkee
Groundwater nitrate* variations NIH, Roorkee
Overall there is a decrease in concentration with depth for all parameters except As for Urban sites. For agricultural sites broad decreases in concentrations with depth are observed for all parameters except F, Se and As which had no clear trend with depth. Highest concentrations for a range of trace elements including As, Pb, Se, and F were found in sites dominated by urban/peri-urban land use, and Pb and NO 3 these were close to or below the WHO guideline value for drinking water. Depth profiles for selected hydrochemistry for different land use a) SEC (ms/cm), b) CFC-12, data from Lapworth et al. (2015, (pmol/l), c) DO (mg/l), d) As, e) NO 3 (mg/l), f) F (mg/l), g) Se (mg/l), h) Pb (mg/l). Solid line shows WHO drinking water guideline values (WHO 2011), dashed line distinguishes deep and shallow sites.
Depth profiles of Uranium and key hydrogeochemical parameters for different land use a) U (mg/l), b) ph, c) Eh (mv), d) HCO 3 (mg/l). Solid line shows WHO drinking water guideline value of 30 mg/l for Uranium (WHO 2011). Dashed line distinguishes deep and shallow sites.
Box-plot of selected hydrochemical parameters by land use and borehole depth a) SEC (ms/cm), b) CFC-12 (pmol/l), c) DO (mg/l), d) ph, e) HCO 3 (mg/l), f) U (mg/l), g) NO 3 (mg/l), h) Pb (mg/l), i) Cl (mg/l), j) As (mg/l). DAgr = deep agricultural, DUrb = deep urban, SAgr = Shallow agricultural, SUrb = shallow urban. Solid lines show WHO drinking water guideline values (WHO 2011).
Stable isotope results Large overlap between shallow and deep GW isotope signatures, No significant difference between prepost monsoon conditions in deep or shallow sites A few shallow sites show evidence of surface water recharge R. Beas alluvial aquifer Evaporative enrichment in some shallow sites No evidence of significant recharge from R. Satluj and related canal system in the south of the catchment Precipitation dominated Evaporation dominated Satluj canal dominated
Q1: Long term GWL data shows evidence of enhanced recharge potential But there are significant parts of the catchment where abstraction is outstripping recharge potential leading to long term loss of shallow groundwater security cost implications for access to shallow GW Q2: Clear evidence, from a range of independent groundwater tracers, that there is significant vertical leakage and recharge from shallow sources to depth (>150) mbgl induced by pumping The natural regional groundwater flow regime is highly perturbed due to pumping and the system can be considered highly isotropic under pumped conditions This has implication for long term groundwater quality protection of deep aquifers and water resource management Reduced shallow groundwater levels in some regions is good news: lower salinity build up, soil waterlogging and of course flooding
NIH, Roorkee
Downloading data (04-04-2016 to 06-04-2016) at Saroya, Bhogpur, Kapurthala and Sultanpur Lodhi
Radon decay Natural radioactivity (half-life) in the ground uranium-238 radium-226 4.5 billion years 1600 years radon-222 gas has time to leak into the air 3.8 days lead-210 lead-206 22 years stable radon progeny (daughters) radioactive isotopes of lead, bismuth, and polonium can be inhaled and deposited in the lungs
STUDY AREA
ACKNOWLEDGEMENTS Funding BGS-DFID, UK- Indo-gangetic study BGS, UK NIH Dr. S.K. Jain, Director Dr. N.C. Ghosh, Sc. G & Head, GWHD Dr. M.S. Rao, Scientist-D, HID IIT-Roorkee Dr. Brijesh Yadav Organizers Dr. A.K. Sahai Dr. Harry Ms Priya Joshi
Thank you NIH, Roorkee
Questions? NIH, Roorkee