Prof A. Balasubramanian

Former Dean, Faculty of Science and Technology

Centre for Advanced Studies in Earth Science

University of Mysore, India

Weather and Climate

Climate Variability

Climatic Observations

Climate Projection

Impacts

Mitigation and Adaptation

There is a saying that climate what you expected and weather is what you get

RAPID & DIRECT CONSEQUENCES ON 1. WATER VAPOUR- HUMIDITY

2. SOIL HORIZON + SEGMENTS OF EVAPOTRANSPIRATION

3. SUFACE WATER RESOURCES

4. SNOW-COVERED REGIONS/ SNOW-MELT FED RIVER BASINS

SLOW- PACED EFFECTS ON1. GROUNDWATER RESOURCES- BUT FULLY

DEPENDING UPON SURFACE SOURCES.

2. SALINE INTRUSIONS

The newer findings indicate that warming is more pronounced than expected.

The impact would be particularly severe in the tropical areas, which mainly consist of developing countries, including India (Sathaye, Shukla & Ravindranath, 2006).

Increasing temperature trends of the order of 0.60°C during last 112 years (IMD 2012) and increase in heavy rainfall events and decrease in low and medium rainfall events (Goswami et al. 2006) over India have been observed.

Changes in rainfall and temperatures have also been reported.

To Sustain the Increasing Temperature –Establish Green Belts, Control Fossil Fuel Emissions, adopt Green concepts

Changing Cropping Pattern/ Changing Irrigation Methods

Manage Evapotranspiration

Maintain Soil Moisture-levels- Infiltration Galleries, Compulsory Ploughing of Lands(old method practiced during 1960s and 70s)

Climatic Change-related Factors- reduction in natural recharge during rainfall deficit periods,

High intensity/ short duration RF= No change

Non-climatic Change Factors- Human Induced-Population, Economic Development, LanduseChanges, Irrigation, Agriculture, Etc

Effects are= over-exploitation beyond capacity of storage, depletion of groundwater resources, pollution, deep bore-wells interconnecting deep fissures/fractures- widening storage space

1. Adaptation to global change must include prudent management of groundwater as a renewable, but slow-feedback resource in most cases.

2. Groundwater storage is already over-tapped in many regions, yet available subsurface storage may be a key to meeting the combined demands of agriculture, industry, municipal and domestic water supply, and ecosystems during times of shortage.

The future intensity and frequency of dry periods combined with warming trends need to be addressed in the context of groundwater resources, even though projections in space and time are fraught with uncertainty.

Short-term simulation through modeling

Enhancing the Water Storage Mechanisms

1. Artificial recharge ( Mandatory- Passing a Bill)

2. Managed aquifer storage and recovery projects may become a more important component of many Govt. or local water systems to bank excess renewable-water supplies and provide water for both normal years and those times when resource shortages may develop.

Establishment of large and small surface water storage facilities will benefit from increased runoff.

There is also a fear that higher carbon-di-oxide concentration in the atmosphere may influence dissolution of mineral substances and alter the infiltration sequences of soils.

There is need to store water underground as part of a larger water management strategy, by considering the role of saturated flow and unsaturated flow in artificial recharge.

The Role of Saturated Flow in Artificial Recharge

The Role of Unsaturated Flow in Artificial Recharge

Aquifer recharge and aquifer storage and recovery wells(ASR)(USPA,1999) are used to replenish the water in an aquifer.

AR wells have been utilized to deter salt water intrusion into freshwater aquifers and to control land subsidence(USEPA, 2009).

AR and ASR wells are drilled to various depths depending on the depth of the receiving aquifer.

Drainage wells include all wells that are used to inject surface water directly into an aquifer, or shallow ground water directly into a deeper aquifer, primarily by gravity(Joel 0. Kimrey and Larry D. Fayard,1984).

Effective use of drainage wells requires a source of injection water (a losing aquifer or surface water); prevailing natural downward gradient from the source to the receiving aquifer; and transmission and storage characteristics of the receiving zone that will allow emplacement of the volumes of injection water without head buildup sufficient to decrease severely the downward gradient.

Establishing drainage wells with adequate densities averaging about 2 to 4 wells per ten square km in the rural and suburban and Direct street stormwater-drainage wells in urban areas may enhance to groundwater recharge for a period of 100 years.

Control pollutants through appropriate methods.

The lake-level control wells receive a mix of rainfall, ground-water seepage, and stormwater runoff during the wet seasons and receive mostly groundwater seepage during the dry seasons.

The wetland drainage wells receive short duration, high-intensity rainfall and stormwater runoff and low, but continuous, amounts of ground-water seepage nearly year round.

Green Strategies for Controlling Stormwaterand Combined Sewer Overflows(Natural Resources Defense Council, 2006).

The urban landscape, with its large areas of impermeable roadways and buildings—known as impervious surfaces—has significantly altered the movement of water through the environment.

Once upon a time under JeevanDhara scheme, we dug million wells ( shallow open wells)

Now, not in use. Is it possible to convert them as recharge wells with lateral drill-holes.

Intensive collection of data & creation of databases

Climate Change Impact on Groundwater –Research Groups

Sharing of Simulation Results

Groundwater resources are related to climate change through the direct interaction with surface water resources, such as lakes and rivers, and indirectly through the recharge process.

Therefore, quantifying the impact of climate change on groundwater resources requires not only reliable forecasting of changes in the major climatic variables, but also accurate estimation of groundwater recharge.

GLOBAL CLIMATE CHANGE

GHG- GLOBAL WARMING RISE OF

TEMPERATURELONG/SHORT-TERM TREND-UNDERSTOOD

CHANGE IN WEATHER

CYCLES

EXTREME WEATHER

EVENTS

FLOODS/ DROUGHTS

CHANGE IN PRECIPITATION

PATTERNS

SPATIAL AND TEMPORAL

VARIATIONSUNCERTAINTY IN MAGNITURE AND

INTENSITY

GLOBAL CIRCULATION MODELS(GCM)

WEATHER PREDICTION

MODELS

PRECIPITATION-RUNOFF

HYDROGRAPH MODELS

RIVER BASIN HYDROLOGY

MODELS

SWAT MODEL

FLOOD FORCAST MODELS

GROUDWATER FLOW MODELS/

TRANSPORT MODELS

UNSATURATED ZONE MODELS

STREAM-AQUIFER MODELS

ISLAND/ SEAWATER

INTERFACE SIM MODELS

WATER QUALITY MODELS

INTEGRATION OF MODELING

METHODS

NATIONAL LEVEL

SCALE OF VARIATIONS

MODELING & SIMULATION

PLANET AS A WHOLE

N-S HEMISPHERICAL

CONTINENTAL LEVEL

REGIONAL / STATE LEVEL

RIVER BASIN LEVEL

WATERSHED LEVEL

SPATIAL :X-DIMENSIONY-DIMENSIONZ-DIMENSION

TEMPORAL : Dt

CENTURYDECADEANNUAL

SEASONALMONTHLY

DAILY/ EVENT

As climate change continues to affect our water resources and elevate threats to public health, water resource managers and policymakers must act quickly to enact well-informed, environmentally sound policiesthat address the threats we already face while preparing for the predicted challenges of tomorrow.

Scientific research can, however, play a key role in the nation’s response to climate change.

The Technological solutions are already available.

Thank you…