Springshed Management Training Curriculum

2016The Springs Initiative

SESSION TITLE:

Hydrogeology of Springs

SECTION: Understanding the ResourceMODULE: Applied HydrogeologyAUTHORS: Dr Himanshu KulkarniCONTRIBUTING ORGANIZATIONS: AcwadamPURPOSE: To introduce the science of groundwater, geology and hydrology in context of springs IMPACT: Participants understand how springs are formed and what distinguishes them from other groundwater or watershed applicationsTIME REQUIRED: 60-100 minutesMATERIALS: This pptADDITIONAL RESOURCES:

Springshed Management Training Curriculum, Draft 2

SESSION TITLE:

Hydrogeology of Springs

Overview• Groundwater, importance/dependence• Water cycle review• Relation to watershed management• Aquifers & groundwater in watersheds• Looking below the ground – rock type, structure• Discharge, relating to aquifer characteristics• Source versus resource• Springshed management approach• Hydrogeology as decision support

Springshed Management Training Curriculum, Draft 2

Global groundwater scenario

www.unesco.org

Groundwater is the world’s most extracted raw material with withdrawal rates currently in the estimated range of 982 km3 /year

Global groundwater abstraction

The water cycle…also called hydrologic cycle

Groundwater is a resource…

• It is a part of a larger system of water resources…the hydrological cycle.

• It is also a part of the larger system of earth resources…THE ENVIRONMENT.

HYDROSPHERE

LITHOSPHERE

PEDOSPHERE

ATMOSPHEREBIOSPHERE

The environment includes spheres and processes

Precipitation

Infiltration

Transpiration

Percolation

Base flows

Watershed management

• Recharge to groundwater

• Control surface runoff

• Conserve and recharge groundwater

• Water security

Watershed management is an integrated effort where rain water is conserved, recharged and harvested.

HYDROSPHERE

LITHOSPHERE

PEDOSPHERE

ATMOSPHEREBIOSPHERE

Base flows

Percolation

Precipitation

Transpiration

Evaporation

Why watershed management?

• Overexploitation of natural resources like• Water

• Soil

• Forest

• Scarcity of water

• Degradation of soil

• Soil erosion

• Frequent flash floodsWatershed management implies to the wise use of soil and water resources.

Hydrological processes…rivers

UPSTREAM

DOWNSTREAM

Hydrological processes…rivers and reality

UPSTREAM

DOWNSTREAM

Watershed approach

Contour trenching, Bunding, CCT, Gabion structures

Check dams,Loose boulder check, percolation tank

Wells, farm ponds

So, where are the aquifers in this watershed??

Spring

Spring

Spring

Hydrogeology helps strategise recharge

Springs and aquifers: discharge trends –annual cycle

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Apr/15 May/15 Jul/15 Sep/15 Oct/15 Dec/15 Jan/16 Mar/16 May/16 Jun/16

Spring 1 Spring 2 Spring 3 Spring 4

Describing a spring based on its discharge

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Apr/15 May/15 Jul/15 Sep/15 Oct/15 Dec/15 Jan/16 Mar/16 May/16 Jun/16

Spring 1

Spring 2

Spring 3

Spring 4

Low discharge, highly seasonal

High discharge, perennial

Sustained perennial discharge

Widely ranging discharge

Spring discharge: accumulation and flow in underlying aquifers

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Apr/15 May/15 Jul/15 Sep/15 Oct/15 Dec/15 Jan/16 Mar/16 May/16 Jun/16

Very limited storage, highly local and seasonal connection to surface water

Large storage, rapid flow

Slow flow, moderate to large storage

Low storage, quick transmission, connection to seasonal surface water source

Spring discharge: mostly likely aquifer types

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Apr/15 May/15 Jul/15 Sep/15 Oct/15 Dec/15 Jan/16 Mar/16 May/16 Jun/16

Very local aquifer

Unconfined / confined

Mostly unconfined

Confined

Indicator matrix

Recharge zone - proximity to spring

Recharge zone - size

Spring 3 Could be either closeby or far away (large aquifer storage)

Large

Spring 2 At distance Small

Spring 4 At distance (moderate to low transmissivity)

Large

Spring 1 Very close Small, probably negligible

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10000

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Rainfall (Melli)

PALLO DHARA

SAUNEY DHARA 1

DAHAL DHARA 1

DWAREY DHARA

…so are springs tapping mountain aquifers

Credit: Mr. Suren Mohra, RM&DD-Sikkim

Baseline= 90 lpm

Impact= 97 lpm

8.33% increase over

the whole year

Baseline= 9.5 lpm

Impact= 10.5 lpm

10.6% increase over

the whole year

Baseline= 16.5 lpm

Impact= 18 lpm

8% increase but over

300 days

Baseline= 11 lpm

Impact= 13 lpm

17% increase but over

80 days

Movement of water from the atmosphere to great depths…

HCO3

HCO3+ SO4+Na+Mg

Na + Cl

Anion change HCO3 SO4 Cl

Cation change Ca Mg Na

An “exposed” aquifer…

Springs! But what else??

?

The aquifer feeding the springs

Morraine

Clay

Aquifer

Spring and a well : what is common ?????

AQUIFER

SourceUsers and uses share a common resource even through different types of sources…

AccessAccess in many areas is through “common” sources…

DistributionDistribution is usually about connecting to a source and supplying to an increasing demand…

What is groundwater?

Groundwater is the water found underground in the cracks and spaces in soil, sand and rock. It is stored in and moves slowly through geologic formations called aquifers.

What is Hydrogeology?

• Hydrogeology is the science of groundwater.

• It is a branch of geology.

• It is a science that deals with occurrence, movement and distribution of groundwater within the geological framework of rocks.

GEOLOGY plays a very important role in the formation of aquifers, and consequently, on the accumulation and movement of groundwater..

Geological conditions tend to vary, both laterally and vertically…

An aquifer is very much like an underground watershed

• Aquifer catchments are areas from where aquifers receive recharge, i.e. groundwater recharge areas or zones.

• Aquifer commands are areas where aquifers send groundwater, i.e. groundwater discharge areas or zones.

• Aquifers are defined by:• Physical (impermeable /

permeable boundaries)• Hydraulic boundaries (constant

/ fluctuating water tables)

Natural recharge

That part of the rainfall (or any other natural precipitation) that infiltrates the ground surface under natural conditions leading to an addition to the groundwater storage, is called NATURAL RECHARGE. It may also be through:

• Direct infiltration through the soil over the whole or part of a watershed.

• From a ponded stock of water.

Artificial recharge• Sometimes, rainfall is collected

artificially and channeled into the aquifer by artificial means. This addition is called artificial recharge. ARTIFICIAL RECHARGE maybe:

• Diffuse: Large pondage is created and recharge occurs through large surface areas.

• Point source: Recharge occurs at specific locations (points) where surface water / rainwater is channeled into wells or bore wells or tube wells (or infiltration pits).

Discharge of groundwater

• Natural: Springs and seeps (baseflow to streams)

• Pumping from wells

• Deep infiltration

Springs and aquifers as commons

Spring is a natural discharge point and its location is irrespective of type of land

Similarly aquifer boundaries also are irrespective to land

type but governed by

local hydrogeology

Springshed development : a hydrogeological approach

Drinking, domestic use,

irrigation, industry etc…

Increasing demand and the

changing climate pattern

Hydrogeology as the base

Spring water used for drinking purpose

Springshed development: conflicts, challenges and

community participation

Lack of data

Lack of awareness of utility of

such data

Geological or aquifer

boundaries rarely coincide

with administrative or

socio-economic boundaries

Springshed development: the scientific process

• Hydrogeological mapping of springshed

• Classification of the spring

• Secondary data collection and interpretation

• Identification of recharge area based on local geology and

structure

• Setting up a monitoring system for periodic spring discharge,

rainfall and water quality data collection

• Delineation of the mountain aquifer

• Planning of treatment measures in the recharge area with the

help of community participation

• Conceptual layout of spring

Springshed development: the final product

A Google image

A geological layout

A Geological map created using

Google image as the base

Springs and its recharged areas marked on a Google image

Use of Hydrogeology in decision support system

Muthalane in Pune district

Aquifer IStorage: 67200 m3

Aquifer IIStorage: 1179200 m3

Aquifer IIStorage: 50000 m3

Aquifer storage= Aquifer area * Thickness * Specific yield

Randullabad in Satara district

Demand-supply management

Randullabad

Rainfall (mm) 600-700

Annual aquifer storage (mm) 151

Annual aquifer recharge(mm)

53

Annual aquifer discharge(mm)

62

Drinking water<1%

Water for livestock<1%

Water for Poultry<1%

Water for domestic use2%

Water for Kharif 17%

Water for Rabi irrigation

81%

Water demand in Randullabad

Efficient use of waterEquitable use of drinking water

Crop planning in Randullabad

Strengthening drinking water sources N

Geological cross section

Geohydrological mapping

Community dialogue

Primary and secondary data collection

Capacity building and communication

Water quality investigation, including past data andHealth data surveys

Estimate groundwater resources availability under various scenarios

Participatory decision making system