2ND FORUM ON SUSTAINABLE GROUNDWATER
RESOURCES MANAGEMENT IN THE VOLTA
BASIN
GROUNDWATER INDICATORS OUAGADOUGOU, 9th and 10th AUGUST 2010
Jacob TUMBULTO, Ag. Director, VBA Observatory
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
PRESENTATION PLAN
PRESENTATION PLAN
1. Introduction
1
2. Characteristics of Indicators
3. Groundwater Data (availability, scarcity, tpye)
4. Considerations for indicator
selection
5. Models of Human – Natural Environment links links
6. Examples of GW indicators
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
INTRODUCTION
What is a Groundwater Indicator?
A groundwater indicator is a numerical value statistic or
A groundwater indicator is a numerical value, statistic or measurement that helps to provide insight into the state of the groundwater or human health
groundwater or human health. Groundwater indicators are tools that serve many purposes (useful as tools for performance evaluation, monitoring the state of resources, public information etc.)
They are developed based on quantitative measurements or statistics of groundwater condition that are tracked over time. g
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Characteristics of Groundwater Indicators
•
•
•
•
•
Should provide a representative picture of the groundwater conditions, pressures on the d t
diti
th
groundwater resources and society's responses;
be simple, easy to interpret; be responsive to changes in the environment and p
g
related human activities;
provide a basis for international comparisons;
provide a basis for international comparisons; be either national in scope or applicable to regional groundwater issues of national significance;
groundwater issues of national significance; have a threshold or reference value against which to compare it so that users are able to assess the it th t
bl t
th
significance of the values associated with it. Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Characteristics of Groundwater Indicators
GW Indicators should be SMART: Simple, GW
Indicators should be SMART: Simple,
Measureable, Achievable, Relevant and Time‐
b
bound
d
• Indicators give the general conditions of the Indicators give the general conditions of the
environment
• Performance indicators compare (f)actual conditions with a specific set of reference
conditions with a specific set of reference conditions.
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Characteristics of Groundwater Indicators
• In general, indicators reflect the situation as it i
it is, without reference to how the situation ith t f
t h th it ti
should be. • Performance indicators compare (f)actual conditions with a specific set of reference di i
ih
ifi
f f
y
()
conditions. They measure the ‘distance(s) between the current groundwater situation and the desired situation (target)’:: ‘distance
and the desired situation (target)
distance to target’ assessment. Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater data: availability Groundwater data:
availability
• Data
Data availability drives the establishment of indicators, availability drives the establishment of indicators,
which, in turn, reinforces collection of data required for more precise formulation of groundwater indicators and leads to more efficient design of monitoring networks
leads to more efficient design of monitoring networks
• Our concept is to rely on the existing GW data with a philosophy of starting small and building on them
philosophy of starting small and building on them
• With the recent advent of spatially discrete and high‐
resolution Earth system data sets, space technology l ti E th t
d t
t
t h l
helps to derive water related indicators.
• Digital data and products are temporally and spatially Di i l d
d
d
ll
d
i ll
coherent, and provide a consistent, political boundary‐
free view of major elements defining the terrestrial
free view of major elements defining the terrestrial water cycle, inclusive of groundwater
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Considerations in Proposing
Considerations
in Proposing
Groundwater Indicators
• The proposed indicator should provide information about the present status of information about the present status
of
groundwater (quantity and quality)
• Should focus on
Should focus on social (groundwater accessibility, (groundwater accessibility,
exploitability and use), economic (groundwater abstraction, protection and treatment requirements) and environmental
i
t) d
i
t l (groundwater (
d t
vulnerability, quality and depletion) attributes of groundwater resources planning policy and
groundwater resources planning, policy and management
• Could be based on a single data
Could be based on a single data (variable) or on (variable) or on
an output value from a set of data (aggregation of variables)
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Two major models of Human –
j
Natural Environment links 1. Pressure‐State‐Response (PSR) Framework
• The Pressure
The Pressure‐State‐Response
State Response (PSR) is based on a (PSR) is based on a
concept of causality which implies that human activities exert pressures the environment and
activities exert pressures the environment and change its quality and the quantity of natural resources
• Society responds to these changes through environmental, general economic and sectoral
i
t l
l
i
d
t l
policies • The responses form a feedback loop to pressure g
through human activities
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
DPSIR
Grands enjeux
& problématiques
Grands Défis
Impacts
State
Responses
Pressure Driving
Force
Grandes Pressions
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater indicators development could follow DPSIR framework
• Driving force indicator – shows the motivation for G water use (eg agricultural development)
water use (eg. agricultural development)
• Pressure indicator – human activities exert pressure on water (N load on farms)
on water (N‐load on farms)
• State indicator – pressure causes a quality/quantity change in the state of water (nitrate in groundwater)
change in the state of water (nitrate in groundwater)
• Impact indicator – describes the effects of the pressure (nitrate in drinking water)
pressure (nitrate in drinking water) • Response indicator – social response to the changes, which are reflected in environmental policy (control
which are reflected in environmental policy (control of fertiliser use and manure production, compensation for lower agriculture production)
p
f
g
p
)
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Indicators of Dependence on Groundwater
p
Indicator
1 Renewable groundwater resources per capita 1.
Renewable groundwater resources per capita
(m3/yr/p)
Evaluation of renewable GW resources is based on
Evaluation of renewable GW resources is based on recharge+ inflow + seepage‐ discharge (base‐flow, springs) –outflow
springs) outflow + artificial recharge, if it is + artificial recharge, if it is
significant
Characteristic
Indicator estimates the total amount of ground water for many uses that exist in the country. This is a driving force indicator (drivers are population growth and climate change) of great significance to th d li t h
) f
t i ifi
t
the planners, policy and decision makers; it has social and economic relevance and supports IWRM
social and economic relevance and supports IWRM
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Indicators of Dependence on Groundwater
p
Indicator
2. Groundwater used for drinking as a percentage of total use of drinking water in
percentage of total use of drinking water in the country Characteristic
Indicator expresses how important
Indicator expresses how important groundwater is for drinking water supply in the country and reflects the social and
the country and reflects the social and economic conditions of the society, accessibility of groundwater resources and bl
f
d
d
their economic value
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Indicators of Dependence on Groundwater
p
Indicator
3. Number of farmers dependent on groundwater for agricultural activities / Total d t f
i lt l ti iti / T t l
p p
population of the country (as %) y(
)
Characteristic
The proposed indicator is designated to signify the importance of groundwater in
signify the importance of groundwater in rural livelihoods and household incomes and provides key information on the importance d k
f
h
g
y
of groundwater for food security
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater Exploitation
p
Indicators
Indicator
4 Total GW abstraction 4.
T t l GW b t ti
x100%
100%
Exploitable GW resources
Exploitable GW resources means the amount of water that can be abstracted annually from a given aquifer under current socio ‐
d
t
i economic constraints and i
t i t
d
ecological conditions
Three scenarios are proposed:
• Groundwater abstraction less the 90% of exploitable p
amount, • Groundwater abstraction = exploitable amount, • Groundwater abstraction more than 100% of exploitable amount
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater exploitation
p
indicators
Indicator
5 (Total GW abstraction x 100%)/GW recharge
5. (Total GW abstraction x 100%)/GW recharge
• Total GW abstraction means the total withdrawal of water from a given aquifer by means of wells springs
water from a given aquifer by means of wells, springs and other means for the purpose of water supply, Agricultural, industrial and other usage. Indicator is calculated as a sum of licensed and unlicensed GW
abstraction and GW natural discharge
Three scenarios are proposed:
• Groundwater abstraction less the 90% of exploitable G
d t
b t ti l
th 90% f
l it bl
amount, • Groundwater abstraction = exploitable amount, Groundwater abstraction = exploitable amount
• Groundwater abstraction more than 100% of exploitable amount
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater exploitation
p
indicators
Indicator
6 T t l
6. Total non‐renewable GW resources / Annual bl GW
/A
l
abstraction of non‐renewable GW resources (as %)
N
Non‐renewable groundwater means that average bl
d
h
annual aquifer renewal is less than 0.1% of the aquifer storage (average renewal period would be
aquifer storage (average renewal period would be at least 1 000 years)
Characteristic
IIndicator can provide an early warning of excessive di t
id
l
i
f
i
use of finite groundwater resource which can also trigger
trigger other impacts such as water quality other impacts such as water quality
deterioration and related social and ecological
consequences
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater exploitation
p
indicators
Groundwater depletion
7. (Σ Areas with GW depletion problem)/ Total studied area (as a %)
studied area (as a %)
Regional GW level declines are associated Regional
GW level declines are associated
with change of base flow, lost of springs, change of groundwater quality, origin and/or age land subsidence and with a high density
age, land subsidence and with a high density of production wells Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater quality and vulnerability
q
y
y indicators
Groundwater vulnerability
8 (ΣAreas of aquifer with different GW vulnerability)/ 8. (ΣAreas of aquifer with
different GW vulnerability)/
Total studied area (as a %)
Three classes of groundwater vulnerability are proposed:
Three classes
of groundwater vulnerability are proposed:
High, Moderate, Low I di t i
Indicator is a very useful tool for land use planning and f lt lf l d
l
i
d
zoning
Characteristic
Indicator expresses groundwater intrinsic vulnerability, Indicator
expresses groundwater intrinsic vulnerability
formulated as a property of a groundwater system that depends
depends on the ability of that system to cope with on the ability of that system to cope with
natural impacts. Vulnerability variables: recharge, soil, unsaturated zone lithology and thickness, aquifer media and hydraulic conductivity.
h
l
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater quality and vulnerability
q
y
y indicators
Groundwater quality
9 (ΣA
9a. (ΣAreas
with natural GW quality problem)/ ith t l GW
lit
bl )/
(Total studied area) X100%
9b (ΣA
9b.(ΣArea with increased concentration
ith i
d
t ti of spec. f
variable)/ (Total area studied) X 100%
SV: Chloride, Nitrate, and EC
hl d
d
Characteristic
Indicator informs about the present status and trends in groundwater quality (natural and under
trends in groundwater quality (natural and under human stress). The strategic value of the groundwater
groundwater in terms of drinking water means in terms of drinking water means
that groundwater quality issues can be high on the g
g
social and economic and ecological agenda
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Groundwater quality and vulnerability
q
y
y indicators
Groundwater treatment requirements
Three categories of indicators are proposed: 10a. Suitable for specific use without treatment (appropriate quality)
10b Si l
10b. Simple treatment needed
d d
(e.g. dilution, aeration, filtration, des‐infection, removal of iron and manganese by separation)
manganese by separation) 10c. Technologically demanding treatment (e.g. coagulation, flocculation, biological methods, membrane methods, de‐
salinization)
Characteristic
Indicator describes whether groundwater can feasibly be made describes whether groundwater can feasibly be made
potable or usable for other purposes with or without treatment (e.g. drinking water, irrigation water, cooling water)
Indicator provides crucial information on groundwater suitability for different uses and its treatment requirements in an easily accessible format for economists, water planners and policy makers
,
p
p y
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)
Thanks for your attention
www.abv-volta.org
Burkina Faso, Bénin, Côte d’Ivoire, Ghana, Mali, Togo
Autorité du Bassin de la Volta (ABV)