Workshop 9:
Safe Water
Storage and Regulation During Floods and Droughts
POSTERS
Transboundary Floods: Conflict, Vulnerability
and Adaptability
Ms.
Co-author: Aaron T. Wolf,
Adaptability and vulnerability of societies to floods are still poorly
understood. However, record temperature extremes resulting in floods continue
to occur, resulting in enormous damage all over the globe. It is therefore
highly appropriate to prepare (more) carefully for the wise management of what
are in many parts of the world increasingly scarce water resources and
acknowledge the potential for catastrophic damage and losses of lives due to
the increase of extreme weather events with an impact on water resources. We
present a way of examining the nexus of extreme weather events and society’s
adaptability to it: how vulnerable are societies to changing circumstances, how
can societies adapt to changing circumstances, what are the lessons learned and
what are the possibilities for cooperation or changes of conflict before or
once the situation has changed. Although water-related extreme events strike
developed and less developed countries alike, and people may face the same
potential risk, they may not equally vulnerable because they may face different
consequences to the same hazard. By comparing a so-called developing (
Methodology
First of all, we investigate the global statistics for loss of human life, the
number of flood-related displaced people, and the total amount of damage in USD per country. Data on floods is obtained from two
databases. The first one is the OFDA/CRED database
which contains data on international disasters like floods and is maintained by
the Centre for Research on the Epidemiology of Disasters (CRED)
in
We continue the study by investigating how decision-makers and institutions in
the case study areas adapted in the past to water-related extreme weather
events? It is assumed that this reaction not only depends on past experiences,
but also on culture, available resources (money, human) – the level of
adaptability - , vulnerability and views of the future. In order to learn from
past experiences with water-related extreme weather events and prepare for
future ones, literature research and case studies focusing on this issue is
conducted. A distinction is made between policy reactions and society responses
in the study areas. The focus is on differences of adaptability and
vulnerability for the case study areas.
Thirdly, we investigate whether lack of flexibility in treaties to deal with
changing hydrologic circumstances cause deteriorating
international relations. Previous studies indicated that many treaties between
riparian countries of transboundary rivers do not
include rules for extreme hydrological conditions such as floods and, though
some do, there is still a risk that agreements were made during a wet climatic
period and do not include enough flexibility to account for hydrologic changing
conditions (Stahl, 2003). Most likely, international water treaties assume
normal hydrologic conditions and therefore rarely mention hydrologic extremes
like droughts and floods. This lack of flexibility can cause conflicts or
deteriorating international relations. Case studies, the Transboundary
Freshwater Dispute Database (TFDD) (Yoffe, 2005) and literature research will list and locate
treaties that have incorporated and that have not incorporated extreme
hydrological conditions.
Findings
First, we discuss the development over time of loss of life statistics, number
of floods, and total amount of damages. We will relate the combined dataset to
the United Nations Human Development Index (HDI) and
show, by means of cross analyses, which a high HDI
score does not necessarily result in lower losses of life or less damage in USD. We will show that there is an uneven distribution
between developing and developed countries it comes to the devastating results
of floods in developing or developed countries.
Second, we present the findings of the literature study which will show
how stressors influence different societies, how dissimilar societies deal with
floods in the past, present and future and what mitigated and mitigates stress.
Lastly, we talk about why and when climatic variability should (not) be
included in international water treaties and theorize about reasons why rules
during extreme hydrological conditions are not included. Recommendations are
given for future international water treaties in areas with higher
vulnerability to water-related extreme weather events.
Living with
the Drought: Strategies for Brazilian Semiarid Region
Mr.
André Teixeira Hernandes,
Co-author: Prof. Dr. Simar Vieira de Amorim
Brazilian water resources occur irregularly by nature and in inverse proportion
from population distribution. The North region – which encloses most of the
Amazonian area – has the biggest water availability (38.5%) but the smallest
population (less than 7%) while the Northeast possesses only 3.3% of
superficial water and accounts for approximately 26% of the Brazilian
population.
The Brazilian semiarid is located in the Northeast with an area of about
900,000 km². It congregates a set of singular and disadvantageous
characteristics - climatic, geomorphologic, social and economical - resulting
in an environment marked by difficulty of access to water. The whole society and regional economy are
affected by this.
By the climatic viewpoint, the semiarid is characterized by strong solar
radiation, lack of clouds, elevated rate of evaporation, little seasonal
variation in temperatures and irregular rainfall regimen with precipitations
concentrated in a short period of time. The annual rainfall data ranges from
350 to 800 mm. The risk of desertification for the area is high as only a few
perennial rivers and water bodies can be found there adding to the fact that
geological conditions for subterranean water storage are unfavorable.
The drought that regularly ravages the area yield serious and lasting
consequences. It concurs to the existence of hunger and other important social
problems as well as to the dissemination of several diseases. The child
mortality index in there is, historically, the country’s highest due to
malnutrition and consumption of poor quality water. This severe poverty picture
leads to compulsory migration in large scale from the rural areas towards the
already decayed, overpopulated urban areas.
In an attempt to mitigate this suffering, a program called “One Million
Cisterns” (1MCP) was created. This program brings together Brazilian and
international non-government organizations (NGOs), as well as Brazilian
government. The idea is to promote a sustainable living between people and the
Brazilian semiarid. Its specific goals are:
• Generate mechanisms
to promote partnership between all the ones involved in the management process
and in society control.
• Bring decentralized
access to water of human consumption grade to estimated 5 million people.
• Strengthen the civil
organizations that take part in the program, to ensure 1MCP will have effective
and efficient performance.
• Unleash an
educational process based in teaching people how to live with the semiarid and
how to form public policies.
• Disseminate concepts
and legitimate practices of living and understanding on the ecosystem of
Brazilian semiarid.
This program is based on the construction of systems to use rainwater,
collected from roofs, floors and natural structures, for human and animal
consumption. The cisterns have 16 thousand liters of
water capacity, enough to ensure water for the needs of a family (drinking and
cooking) in the course of the eight months of dry weather. The cisterns are
built by local masons, formed and qualified by the 1MCP along with the
families, who are put in charge of excavating, sand and water acquisition and
involved in the construction itself. This simple technique, largely
disseminated in other world’s regions, allows this group of people to be
reinserted in society. The minimal
survival requisites are guaranteed and the adequate soil exploration techniques
are adopted, thus resulting in a pronounced improvement of social and
economical conditions. Another consequence is that the role of women and
children are significantly altered. The women have the chance of becoming
economically active by manually transporting the necessary water and the
children can go to school.
The following techniques are used to guarantee supply:
• Traditional cistern: water is caught from roofs and protected surfaces. After treatment, can be used for human consumption.
• Cistern, adapted for agriculture: with a 16 m3 cistern it is possible to use
the water for small areas irrigation, where greens or seedlings are cultivated.
It’s also possible to raise small animals like poultry or bees.
• Water hole: shallow well, for all kinds of uses.
• Subterranean dam: makes good use of running water from rain or small streams
available in the area. When the dry season comes, the flooded area keeps
moisture thus being available for fruits, greens and annual crops planting. It
can also supply water for animals trough digging a
well.
• Loam-pit: Developed to store water for animals and for irrigation,
complementing annual crops needs.
• Small dam: Cultivation is carried out at its margins, downstream, or at a
lower area with irrigation.
• Stone tank: it’s a natural cave, carved on large rocks; excellent rainwater
collector tank for all uses.
• Mandala: it’s a permaculture
technology adapted for the semiarid that streamlines and optimizes a small
conic reservoir’s water use for drip irrigation of horticultures established in
its vicinity. These horticultures may also be associated with raising fish and
poultry.
• Roadside water harvesting: rainwater that runs on the side of roads is
harvested, conveyed, stored and can be used for irrigation.
So far the aforementioned program has been established in 897 towns of the
region with the following results:
• 97,300 families involved;
• 87,300 families already qualified in Water Resources Management, Living in
the Semiarid and Citizenship;
• 2,800 masons trained;
• 85,600 cisterns built
We can imply from this process that when civil society gets mobilized and joins
force it’s partnership with government is strengthened and public policies,
like the ones aiming semiarid development, are optimized. Numbers are showing,
already, that the participative system of the 1MC Program promotes bonds among
members of society and gives them directions to get organized to a better
social and economical development of the region.
UTILIZATION
OF STORMWATER RUNOFF FOR GROUNDWATER RECHARGE THROUGH
A SYSTEM OF EXISTING PONDS/TANKS – A FEASIBILITY STUDY FOR AN URBAN AREA
Prof.
PREAMBLE: Availability of assured water resources in urban areas is
becoming increasingly difficult. Groundwater resources are depleting at
alarming rates of 1.0-3.5 m/year in several arid and semi-arid zones. This necessitates
recycling, reuse and recharge, after adequate safeguards, of available water
resources as well as wastewater.
With thrust on infrastructure development, urban areas are being provided with
an underground drainage system of the type separate system in place of existing
system of individual septic tanks and roadside open drains. However, open
drains are also in use for drainage of stormwater
runoff and for drainage of unsewered areas. Several
of the urban areas are endowed with small lakes/tanks/ponds. However, several
of them, unfortunately, are encroached resulting in closure/blockage of feeder
drains/supply channels. Some of the tank beds are converted into residential
housing colonies even by government agencies with scant regard for water resources.
The proposed system envisages a system of roadside surface drains to collect
and carry stormwater runoff from roof tops, paved
backyards and frontages and from streets/roads and discharge the same into
local lakes/tanks/ponds for groundwater recharge. Feasibility of such a system
was examined for an urban area and presented herein.
DESCRIPTION OF STUDY AREA: The urban area , Tirupati
- a renowned pilgrim place in Andhra Pradesh, India - spread over an area of
more than 40 km2 is in a semi-arid region and receives an annual rainfall of
80-120 cm. Stratigraphically, the urban area and its
environs fall in the Precambrian sedimentary groundwater province and
groundwater occurs in the top consolidated zone to a depth 20-30 m or
in the fractured or weathered zone
at a depth of 40-50 m and is confined to a depth of 150 m or so.
Groundwater yield is in the range of 5-200 m3/day with varying drawdown.
The study area is endowed with more than twenty small (0.5-5.0 ha) and major
(>10 ha) lakes/tanks/ponds with a total water spread area of around 150 ha.
The tank beds are mostly of silty clay or clayey silt
with seepage in the range of 10-4 – 10-6 cm/s and is in the border of pervious
and impervious soil formation type and falls in the weathered layer/jointed
horizons. The area is hilly terrain with favoring
relief.
PROPOSED DESIGN METHODOLOGY: Based on a study of the topography and relief maps
and considering the proximity of lakes/tanks/ponds and sloping patterns, the
urban area is divided into twelve mini catchment
areas. Each mini catchment area comprises of several
residential and other buildings, streets and roads and vacant lands grouped
together and would contribute stormwater runoff into
respective lakes/tanks/ponds. From the characteristics of the catchment area, appropriate impervious factors, time of
concentration and time of travel are estimated. From the rainfall data,
intensity and duration of occurrence of rainfall for a 10 year design period
was determined and the runoff calculated. A network of hydraulically efficient
drains of trapezoidal cross-section with a side slope of 790 to the horizontal
are so designed to discharge individual and cumulative stormwater
runoff into subsequent and proceeding drains and finally into respective
lakes/tanks/ponds. Treatment of the tank bed to improve rate of seepage,
strengthening of the bunds and increase in the height of the bund to
accommodate cumulative runoff are all suggested. Appropriate overflow devices,
silt/sedimentation traps and diversion of excessive flow are also incorporated
in the design.
CONCLUSION: Increasing demand of water coupled with depletion of groundwater
table at alarming rates and necessity of a separate system for draining stormwater runoff prompts utilization of stormwater runoff for groundwater recharge. Existing
lakes/tanks/ponds within the urban area may be utilized for groundwater
recharge. Urban area is divided into mini catchments and runoff from mini
catchments is collected through a network of drains and let off into respective
lakes/tanks/ponds for recharge of groundwater. Adequate safeguards like stormwater overflow devices, silt/sediment traps are
suggested. Implementation of such a system would accomplish dual objective of stormwater drainage and groundwater recharge and would
greatly improve the groundwater resources of the region and augment water
supply.
Impact of
Seasonal Changes of the Ecological Condition of Water Storage on Drinking Water
Quality
Prof. Nataliya Klymenko,
Presentation/topic: A considerable part of
N?? is one of the most critical components of surface
water and may control such phenomena as mobility of heavy metals and
hydrophilic organic matter in water. N??, to a great
extent, determines the drinking water quality. NOM is a source of organic
carbon for microorganisms and consequently the cause
of secondary microbial pollution and biofouling of
treatment plants and distribution networks, the cause of toxic chlororganic compounds being formed in drinking water.
Analysis of the state of a natural water reservoir and reasons for its changes
during different periods of the year will enable us in future to forecast
changes of technological modes of water treatment plants depending on changes
of the aquatic ecosystem condition.
As an object of investigations we selected the Kremenchug
Storage on the Dnieper River. Indicators of water
quality were determined in the water of the Storage proper and after the water
supply treatment plants during the period of 2001-2004. On a monthly basis we
determined color, COD, permanganate oxidizability, BOD, dissolved
oxygen, content of ammonia, iron, and manganese.
Formation of water quality in the Dnieper River and
its storages in the upstream region is determined primarily by the presence of humic matter of marsh origin and its value amounts to
XVIII-?I? divisions of the standard scale of color. In the Kremenchug Storages
the color varies in the range from
?II to ?VII divisions. Variation of the water color
in a cascade of water reservoirs is related to changes of soil types along the
course of the river, formation of NOM of plankton origin, floods or arid summer
periods. N?? of
marsh origin is an old-formed matter, while that of plankton origin is a
newly-formed matter. It determine peculiarities of
their behavior in water treatment processes. Analysis
of hydrochemical and physicochemical characteristics
of water may provide information on the chemical nature of NOM of different
origin and its changes in different seasonal periods (during floods or droughty
periods). This makes it possible to correlate the process parameters of
drinking water treatment during different periods of the year.
Presentation of results. We showed that data on the
origin of NOM in water can be obtained by comparing the ratio of color and oxidizability. A higher
value of this ratio indicates a predominant content in the water of stable humic substances of marsh origin. The ratio of humic compounds of marsh or plankton origin depends on
seasonal or annual climatic conditions. Humic
substances of plankton origin prevail in the period of floods, while humic substances of plankton origin are more abundant
during arid periods of the year.
For example, the lowest value of color-to-oxidizability
ratio of 2.5-3 was registered in the dry 2002. This fact indicated a
predominant content in the water of humic matter of
plankton origin. A sharp rise in the ratio during certain periods of 2001 (up
to 5.2) and 2003 (up to 5.0) is the evidence of the growing content of humic matter of marsh origin. This statement is corroborated by
correlation of these indicators with the rise of ammonia content and the
reduction of oxygen content in the water. It is related to the intensive summer
rains during this period of the year in the upstream region of the Dnieper River. Owing to rains the overflow land areas were
flooded. In order to reduce the area of flooding and prevent the penetration of
radioactive nuclides into the water of upper reservoir, its water was rapidly
discharged in forced manner. That is why the reservoir was filled with high color waters of tributaries of the Dnieper
River from marches of Polesye. The front of Polesye water on its course along the cascade reached the Kremenchug storage. The reduction of water level in the
reservoir also contributed to the rise of color of
its water resulting in the growing share of the Polesye
run-off and reduction of the dilution factor in the storage.
Similar analysis of changes in all indicators of the water quality in the Kremenchug storage was carried out on a monthly basis in
the period of 2001 – 2004. The variation and relationship of these indicators
was shown to depend on floods or abundant rains. We carried out the performance
analysis of water supply treatment plants during the same period of time.
It was revealed that indicators of the drinking water correlated with variation
of the chemical composition of natural organic compounds during the four years
of observations. Hence, the standardized indicators of drinking water were
achieved at the level of color-to-oxidizability ratio
equal to 2 – 3. As this ratio increased to the level >3, the quality
indicators were above the standardized ones. Such analysis was executed in
respect of all indicators of the drinking water quality.
Conclusion/recommendations
- Critical analysis of
hydrochemical and hydrobiological
conditions of water makes it possible to establish the regularities of
variation of the water quality during different periods of the year and the
reasons of its deterioration owing to natural and anthropogenic factors.
- Processes of
self-purification of water in the reservoir should be intensified during
different periods of the year by using aeration in the region of drinking water
intake.
- Estimation of
barrier capabilities of each water treatment process must be linked with
changes of hydrochemical properties of water in
reservoirs and with due regard for conditions of flood or drought.
OPTIMIZATION
OF OPERATING POLICIES OF MULTI RESERVOIR SYSTEMS USING GENETIC ALGORITHMS
Dr. Shervin Momtahen,
Iran
Mosharab C. E.
Co-author: Dr. Alireza Borhani
Dariane
Finding optimal operating policies for a reservoir
system has been a major area of study in water resources systems for several
decades. Various kinds of optimization models are developed as the best tools
to identify reservoir operating policies. However, there are some computational
restrictions in these models especially in optimization of multi reservoir
systems. So they are not able to represent the complex physical and
hydrological characteristics of the system adequately.
A Genetic Algorithm (GA) model is proposed in this
paper as a new optimization model of multi-reservoir systems operation and has
shown to be very promising. This real coded GA is
used in a direct search optimization approach and compared this some models of
two other main optimization approaches of explicit stochastic optimization (ESO) and implicit stochastic optimization (ISO). In the
proposed GA model, the policy parameters are directly
optimized using the simulation results of the system as the fitness functions.
Hence, the model has some good properties which make it able to optimize
different kinds of reservoir systems, even large multi-reservoir ones.
Various forms of operating policies from simple and piecewise linear to more
complicated ones like artificial neural networks are considered and optimized
by this method. In selecting the operating policy form, the idea of a principle
like the principle of parsimony of parameters in time series modeling is approved by the results. A new method is also
proposed to define the time variations of policy rules, in stead of the
conventional method of separable monthly rules. By this method, the policies
are defined as a unique rule in which the operating periods of year is
considered as an input variable. All the policy coefficients are considered as
a Fourier series in which time of operating is its independent variable.
Parameters of these Fourier policies are less in amount. Therefore the
optimization computations can be reduced and the optimized policies are more
reliable in future operations.
The conventional real coded GA is modified by
changing its operators to enhance its computational performance. The idea of
some of the modifications is come from Evolutionary Strategies (ES). The
modified GA using adaptive normal mutation and blend
crossover is remarkably faster and more effective than the conventional one in
multi-reservoir systems modeling. Sensitivity of the
performance of the model to its executive parameters (like population size of generations
or probability of mutation and crossover) and variation of final results in
different runs are also reduced in the modified model.
A varying period simulation method is also proposed to evaluate the fitnesses of GA chromosomes
faster. Fitness of first generations chromosomes can be evaluated using
simulation of a small part of historical time series since GA
is exploring the state space of the problem in the start of computations.
Length of simulation period would be increased generally in the next
generations to get to the whole historical series. Computational time of
optimization is therefore reduced by this method and the final results of the
model are as accurate as the fixed length simulation method.
The modified GA model is evaluated by two simple
reservoir systems with one and three reservoirs and then applied to Dez-Karoon 16-reservoir system as the largest
multi-reservoir system in
The results of simulations using historical data show that the performance of
the GA policies is quite superior to the conventional
ones. The GA model has shown to be flexible and
robust, even in optimizing nonlinear, non-separable objective functions and
constraints. It is a promising method for identifying operating policies for
complex multi-reservoir systems. The model is very useful especially when the
reliability is the objective function of problem or one of its constraints or
even in multi-objective optimization.
Alluvial
aquifers as potential safe water storage in semi arid areas: Case study of the
Mr. William Moyce,
Availability worldwide of fresh water for human use is becoming an
increasingly difficult resource to ensure and sustain particularly in semi-arid
climate. Semi-arid regions are faced with problems of limited surface water
resources due to high evapo-transpiration, low
seasonal rainfall and vertical seepage losses to bedrock. Studies done in the
Lower Mzingwane Catchment,
LandSat TM imagery was used to identify alluvial
deposits for potential groundwater resources. On the false colour composite
band 3, band 4 and band 5 (FCC 345) the alluvial
deposits stand out as white and dense actively growing vegetation stands out as
green making it possible to mark out the lateral extent of the saturated alluvial
plain deposits using the riverine. The alluvial
aquifers form ribbon shaped aquifers extending along the channel and reaching
over 20 km in length in some localities and are enhanced at lithological
boundaries. These alluvial aquifers extend laterally outside the active
channel, and individual alluvial aquifers have been measured with areal extents ranging from 45 ha to 723 ha in the channels
and 75 ha to 2196 ha on the plains.
The distribution of these aquifers, is determined by
the river gradient, geometry of channel, channel width, loss of stream flow by
evaporation and infiltration and rates of erosion. Enhancement of alluvial
aquifers may be associated with geological boundaries, occurring both upstream
and downstream of the geological contact and these enhanced aquifers have been
noted to have good storage potential. The lithologies
on either sides of the geological contact will exhibit different degrees of
resistance to fluvial erosion. The alluvium will accumulate on the less
resistant lithology, either upstream or downstream of
the resistant lithology. Mazunga
Ranch has a resistant lithology (silicified
sandstone) downstream and Bwaemura and resistant lithology (gneiss) upstream. These enhanced alluvial
aquifers form big pockets, which have great potential for water storage during
the dry season and drought years. Estimated water storage potential ranges
between 175,000 m3 and 5,430,000 m3 in the channels and between 80,000 m3 and
6,920,000 m3 in the plains Such a water storage potential can support
irrigation ranging from 18 ha to 543 ha for channels alluvial aquifers and 8 ha
to 692 ha for plain alluvial aquifers. Artificial alluvial dams can be
constructed to increase the storage capacity of the aquifer and thereby store
enough freshwater for the dry season.
Recharge of the alluvial aquifers is generally excellent and is derived
principally from river flow and full recharge normally occurs early in the
rainy season. By contrast for lateral plains aquifers, recharge depends on the
permeability of the aquifer, the distance from the channel and the duration of
river flow. Some alluvial aquifers may be recharged by surface water dam
releases during the dry season, such as the Zhove dam
on the Mzingwane River.
The water quality of the aquifers in general is fairly good due to regular
recharge and flushing out of the aquifers by annual river flows and floodwater.
The different grains sizes from clay size to gravel size in the alluvium
profile can act as filters making the water free from bacterial contamination.
Water salinity was found to increase significantly in the end of the dry
season, and this effect was more pronounced in water abstracted from wells on
the alluvial plains. During drought years, recharge is expected to be less and
if the drought is extended water levels in the aquifers may drop substantially,
increasing salinity problems. To avoid salinity problems, integrated water
management is needed to utilize the plains and river channel aquifers
conjunctively. Abstraction rates and water quality should be monitored to avoid
salinity problems of the river channel aquifers during the dry season and
drought years.
Evaporation losses from the channel sand beds are initially high, but decline
as the water table declines to approximately 90 cm below the sand bed surface.
On the alluvial plains with finer grained soil, the evaporation extinction
depth may be somewhat deeper. Therefore alluvial aquifers can be good water
storages in semi arid regions where high evaporation rates prevail. Currently some
of these aquifers are being used to provide water for domestic use - J.Z. Moyo School and Mtetengwe Village, livestock watering and dip tanks - Kwalu, commercial irrigation - Mazunga
and Gem Farms, food security scheme - Kwalu
Irrigation Scheme and market gardening -. Bwaemura Village. Alluvial aquifers can sustain small-scale
irrigation and infiltration galleries and well point systems can be constructed
to exploit the groundwater resource.
Integrated
Rainwater Harvesting and Management Systems and Complementary Technologies for
Sustainable Livelihoods of Pastoral and Agro-Pastoral Communities in Greater
Horn of
Mr. Stephen Ngigi,
University of Nairobi
Most of the Greater Horn of Africa (GHA)
countries are experiencing profound socio-economic and political problems, the
most dramatic being food crisis and disruptive conflicts. In particular, the
pastoral and agro-pastoral communities in ASAL, which
covers more than 70% of the area, have been experiencing a combination of both
short-term, often acute food crisis, and long-term or chronic food shortages
due to the negative effect of recurrent drought on their livestock which is the
main source of livelihoods. Long-term or chronic food shortages often translate
into famine and starvation, requiring emergency food aid. The latter are less
obvious, for they are characterised by negative changes in the economic, social
and ecological factors and their interrelationships over longer time periods.
These crises threaten the stability and existence of the affected communities
and economies because their systems are obviously failing to cope, increasing
the vulnerability of the people. A number of explanations have been advanced
for the endemic food insecurity and poverty in the GHA.
Among these, recurring drought and unreliable rainfall are the most obvious.
These include: adverse weather and drought; rapid population growth rates that
exceed rates of food production; adoption of production systems that accelerate
environmental degradation and decline in fertility; retrogressive social
organizations, inadequate policies, legislation and institutional weaknesses.
The livelihoods of the pastoral and agro-pastoral communities living in the
marginal areas of GHA are periodically affected by
recurrent droughts, floods and other environmental disasters. To respond to the
critical needs of these communities, Rainwater Harvesting and Management (RHM) systems and complementary technologies have shown
positive socio-economic and environmental impacts. Rainfall in these areas is
low, annually ranging between 250-800 mm, it is poorly
distributed and occur in heavy storms, which some times cause flash floods and
loss of human and livestock. RHM systems—collecting,
storage and management of surface runoff and floods, especially in water pans
or earthdams have proved to be an essential source of
much needed water especially for livestock, domestic and micro-irrigation.
However, poor sanitation and environmental management leads to deteriorating
water quality especially for domestic purposes. This problem was addressed
through improved sanitation and environmental conservation to reduce water
pollution and soil erosion respectively. Good quality water will reduce water
borne and related diseases that mainly affect children.
The project also promoted water management related and complementary
technologies such as drip irrigation for vegetable production, rangeland and
watershed improvements, bee keeping and honey production, improved sanitation,
establishment of tree and vegetable seedlings nurseries, fodder/hay production
and management (bailing) and sustainable natural resources management.
Therefore, an integrated and multi-sectoral approach
to rural development was adopted to bring together various stakeholders working
with the same communities and enhance realization of socio-economic impacts.
The overall objective was to establish three community-based pilot sites for
promoting integrated RHM systems and complementary
technologies with the aim of enhancing sustainable livelihoods of pastoral and
agro-pastoral communities in Kenya. Two pilot sites (Isinon
in Kajiado district and Wamani
in Laikipia district) were implemented through
financial assistance from USAID/DCHA/OFDA while
German Development Service (DED) funded the other
site (Kimalel in Baringo
district). The specific objectives were:
• To increase water
availability and management;
• To improve sanitation
and water quality;
• To improve food
security and alternative livelihoods systems;
• To improve pasture
and fodder production and management;
• To build the capacity
of local communities to ensure sustainable natural resources management; and
• To disseminate
information and share experiences among the stakeholders.
The project results have shown that integrated RHM
systems and complementary technologies can drastically improve the livelihoods
of marginalized communities and make the vast drylands
in GHA more productive. The project has been well
received by stakeholders due to its verified impact indicators and changed
communities’ perception. However, replication of the pilot project would not be
successful without the participation of relevant multi-sectoral
stakeholders. The project results also
show that there are economically viable, simple and environmentally friendly
initiatives that can address the persistent drought and famine in GHA. The proposed poster will highlight the implementation
process and results of the pilot project.
Irrigation
and Flood Control Strategies in southern Indian state
Dr. Joseph Sebastian Paimpillil,
Envirosolutions, Center
for Earth Research and Environment Management
Co-author: S. Thomas
Irrigation Department, Government of Kerala
Optimal utilization of the water resources through appropriate
conservation and management measures assumes critical importance in sustaining
the life support systems. The southern Indian state (Kerala)
has 44 rivers and has ample rainfall for about 72,000 million m3 of water every
year, only 5.5 % gets stored in medium irrigation and hydro-electric dams.
Nearly 40 per cent of the resources are lost as run off causing heavy floods.
During monsoons, the rivers get filled up soon after the rain it goes dry
again. This is because the annual average water discharge through the river is
simply allowed to flow into the sea. In the case of biggest river Bhrathapuzha ,
about 96-97% of 4000million m3 of water of passes to the sea during monsoon
months. Although the country enjoyed normal monsoons through out the period
1989-2000, each of these years witnesses deficient rainfall in anything between
12 and 35 % of the districts. India witnessed one of the worst droughts in 2002 in the past
hundred years. The Check dam construction is the cheapest and most effective
way for water conservation in this region.
The ground water resource is estimated at 7048 MCM. Its ground water levels are falling, its
rivers, canals, lakes and backwaters are shrinking, and its people are reeling
under a severe shortage of potable water.
Priority in resource allocation (69% of total) in Kerala
was given for major and medium irrigation projects for rice crops, but not
succeeded in increasing the area irrigated or productivity or in returns. Minor
irrigation schemes are best suited for irrigation in Kerala,
but adequate priority was not given in the allocation of resources. Ground
water development also comes under minor irrigation. Around 25 per cent of the
ground water resource potential has been tapped and the coastal and low-lying
regions of the midland offer good scope for ground water development. Out of
the 152 blocks in Kerala, eight have been identified
as critical, six as semi critical, two as over exploited and 136 as safe.
Traditionally irrigation management has been considered as a departmental
exercise without any provision for participatory approach either in the
selection of the works or in their execution and management. Local level Water
Resources Development and Management through participatory approach to be given
a thrust to attain sustainable local self-sufficiency regarding water
requirements. Recent communities Irrigation Project with the active
participation of the beneficiary communities have drilled 131 bore wells.
Several minor irrigation schemes have been taken up recently as local
governments have to spend about 40 per cent of their allocation in productive
sector. A good number of schemes have not resulted in increasing water
availability as undue emphasis was given to protective structures. In flood
control, most of the schemes are related to relief work for the affected areas.
Flood control works continue to be on conventional lines. The identification
and execution of works are on adhoc basis and largely
based on public pressure and there is no system for the assessment of needs and
priorities. Basin wise studies are required for the identification of flood
prone areas. A strategy for water resources development and utilization for
irrigation and other purposes envisaged for the coming years includes the
revamping of 1st and 2nd generation irrigation projects to improve the current
level of utilization by taking into account the changes that have taken place
over time and bringing about necessary modifications with the partnership with
local governments and user groups. Water resources planning and management to
be taken up by the river basin level by aggregate watershed based plans
prepared locally. Special focus would be given to revival, conservation and up
gradation of local water resources and traditional systems of water management.
Ground water exploitation would be based only after proper zonation
and with the involvement of farmers at the local level. Technical support for
development of groundwater sources and helping farmers for acquiring sources of
irrigation on individual as well as self help basis are features included under
future programme.
Reservoir
Regulation under Conflicting Flood and Conservation Storage Demands
Mr. H. K. Varma,
Central Water Commission
Co-author: Mr. R. Jeyaseelan, Central Water
Commission has Masters Degree in Civil Structural Engineering and PG Diploma in
Hydropower Development from the Norwegian Technical Institute.
Presentation of topic: Water is critical for long-term economic
development, human health, social welfare and environmental sustainability. The
demand of water for various end uses such as irrigation, drinking water supply,
industries, power generation, fisheries, navigation, and recreation is ever
increasing because of the ceaseless rise in human population associated with
increased urbanization, industrialization, agricultural activities and increase
in standard of living. All these essentially require storage, diversion,
conservation and management of usable water resources and, most important among
them being construction of reservoirs and their operation, which balances the
temporal and spatial variability of water as available in nature. There is
every indication that the need for storages will grow due to anticipated
impacts of climate change, which could result in rapid glacial melt and
increased variability of rainfall in large parts of the subcontinent leading to
occurrence of extreme events of floods and droughts.
Irrigation, domestic, industrial and other demands are best served by
conservation storages requiring reservoir to be full during any filling period,
whereas, flood management requires empty storage space for absorbing the
incoming floods and moderation. The conflicting requirements in terms of
storage space requirements could be managed through suitably planned reservoir
operation. The storage could be either single purpose or multipurpose reservoir
and single or multiple systems. While flood control requires lower reservoir
levels, conservation interests require as high a level as is attainable,
necessitating a compromise on these uses. In India major floods occur during
the south-west monsoon season (June to October). A part of the conservation
storage is utilized for flood moderation during various stages of the monsoon,
which is filled up towards the end of monsoon progressively, which naturally
involves some sacrifice of the flood control interests. Regulation of
multipurpose reservoirs shall be based on the priority of one use over the
other.
Two cases, one of regulation of single multipurpose reservoir (Ukai dam) and the other of a system of multipurpose
reservoirs (DVC System) are presented here.
Single multipurpose reservoir: Tapi is the second
largest west flowing interstate river in the peninsular
Under the above limitations, the reservoir was operated optimally, with the
help of the inflow forecast system installed. The maximum 12 hour average
outflow was contained at 13,956 cumec against the
average inflow of 21990 cumec resulting in a flood
moderation of 36%. In terms of the peak
flows, the inflow peak attained was 25,949 cumec and
the outflow peak was 14,870 cumec giving a relief of
over 42%, thus averting a major calamity, which would otherwise have occurred,
in the absence of the dam. In view of the flood damages that occurred even at
this reduced outflow, the warning and danger levels for Surat
city have now been reduced from 10.18m and 11.18m down to 8.5m and 9.5m respectively.
System of multiple reservoirs: Damaodar Valley
Corporation (DVC) system of reservoirs consists of
four dams at Tilaiya, Konar,
Maithon and Panchet (with
flood storages), Tenughat (without flood storage) and
a Barrage at Durgapur. The envisaged principal
utilisation of the stored water is for Kharif (June
to October) and Rabi (November to March) irrigation, hydropower generation,
water supply for industrial & domestic uses and flushing doses during the
monsoon season. Total designed storage capacity of first four dams is 3600 MCM with flood retention capacity of 1860 MCM, but restricted to only 1290 MCM
due to land acquisition problems in respect of Maithon
and Panchet reservoirs.
The bankful capacity of the river Damodar
at Durgapur is only about 7,080 cumec,
but due to siltation of the river bed and
encroachment of the flood plains, the safe capacity below Durgapur
barrage has reduced to 3,680 cumec only and, 2,830 cumec in the lower areas where there is heavy rainfall
coupled with high tide and spilling of tributary Dwarkeswar.
Keeping in view the above limitations, flood damages in the lower valley were
minimized by controlling the releases below 2,830 cumec
as far as possible. Combined releases from Maithon
and Panchet dams are regulated in four slabs
depending on the flood reserve occupied.
With planned regulation of reservoirs along with flood forecasting network, it
was possible to moderate inflow flood peaks of 14606 cumec
to 4536 cumec for 1961 flood, 16726 cumec to 4979 cumec for 1973 flood,
22036 cumec to 4612 cumec
for 1978 flood and 17585 cumec to 7121 cumec for 1995 flood. Demands for kharif
and rabi irrigation,
industrial and municipal supplies, mandatory flushing release, carry over
storage in Maithon reservoir and generation of hydro
power were managed successfully.
Conclusions and recommendations: Dams play a major role in minimizing flood
damages by providing flood cushion and regulation based on sound operation
policies supported by well established flood forecasting network as borne out
amply by the case studies presented. In addition to the optimal operation of
the reservoir, flood forecasting enables issue of flood warning to the people
likely to be affected, well in advance of about 48 to 24 hours. Since absolute
flood control and protection to all flood prone areas for all magnitudes of
floods of different probabilities of occurrence are not techno-economically
viable, a reasonable degree of protection from flood losses at economic costs
can be achieved by management of flood using both structural and non-structural
measures. Constant review of the reservoir operation policies and rule curves
are required for optimizing the storage of incoming flood waters in the
reservoir so as to control the magnitude of the flood downstream as well as
maximize conservation storage.
Enhancement
of Groundwater Recharge in Upper Water shed Areas to
K.A.W. KODITUWAKKKU,
WATER RESOURCES BOARD
In recent past, it was observed significant depletion of river base flow
in several river basins during drought periods in Sri Lanka. This situation may
effect for groundwater regieme of downstream areas.
In addition, this situation no doubtedly
affect water supply schemes mainly in large scale domestic and
irrigation water supplies. The main causes observed as variation of rain fall
pattern and some man made activities in these river basins. Meantime water
demand for various
development activities is being gradually increased and nearly
100 of town water supply schemes suffer from reliable water intakes to cater
future demand. Therefore it is necessary to implement sustainable water
resources management programme to over come this situation. In this aspect, it
is important to implement water conservation program on river basin level. To
initiate this concept, sub basins of Deduru Oya river , Sri Lanka, has been
selected to study the possibilities of increasing groundwater recharge in upper
water shed areas to increase river base flow of downstream areas, specially in
dry zone . Due to prevailing geological , geostructurel and geomorphological
characteristics of the selected area, which is hard rock terrain, there are
possibilities to improve river base flow by improving groundwater recharge, as mentiond above. In this paper it is intended to present some special behavior of surface water and groundwater in the selected
river basins and possible approach to carryout groundwater modeling.
Groundwater flow pattern in fractured hard rock aquifer areas are considered to
prepare conceptual modeling of ground water in order
to forcast expected
baseflow after increasingt
groundwater recharge of upper water shed areas of the river basins.
Are Floods
and Droughts the fate of
Mr. Hasan Basri Yuksel,
Public Institutation
Are Floods and Droughts the fate of Turkey?
Before the explanation of drought and flood events in Turkey, it would better
to look at the water resource potential in Turkey. The average annual
precipitation in Turkey is 650 mm. When we multiply this figure by the Turkey’s
780 000 km² surface area, we get 501 km³ water volume.
About 274 km³ water volume returns to atmosphere by evaporating from water
surfaces. The average annual surface runoff is 186 km³ of which 98 km³ can be
developed for consumptive use. Adding the 14 km³ of groundwater safe yield, the
total amount of annual exploitable water has been assessed as 112 km³. However,
only about 40% of the total water potential is consumed currently thanks to
constructed water storage facilities. Turkey targets to develop all exploitable
water potential by the year 2030 in which Turkey’s population is estimated to
reach 115 million. Then the annual available water per capita will fall below
critical level 1,000 m³ per capita. This amount seems enough for irrigation,
domestic and industrial water supply needs, but it does not occur in the right
place at the right time.
First it would be better to understand when droughts occur and what the
measures can be for mitigating its effects. In the inner part of Turkey,
altitude of the plain land is lower than the surrounding mountainous coastal
areas. The ideal picture is that all the surface of Turkey is to be receive necessary amount of precipitation dispersed all the
surface area of Turkey, all the years, and within the year. But, the fact is
quite different. The distribution of precipitation in Turkey is rather uneven.
Turkey is subject to both a continental type of climate characterized cold
rainy winters with dry summers and subtropical climate identified by dry
summers. Generally 70% of total precipitation falls from October to March and
there is little effective rain during summer to meet irrigation needs. The
coastal areas receive more precipitation but average annual precipitation in
inner parts, which consist of the majority of the land surface, is 250 mm.
During the critical period, this figure drop dramatically and may last more
than one year. Consequently droughts occur. The first sector to be effected is
the agricultural, which is responsible for consumption of about 70% of the
water consumption. When data obtained by meteorological stations, observation
stations on rivers and on water storage facilities indicate probable critical
period, farmers are to be warned not grow plants that summer that need more
irrigation. Saving water is especially important in water scarce regions.
Therefore modern irrigation systems are to be preferred to traditional
irrigation systems. Closed irrigation systems with pipeline distribution
systems save 10% of open conveyance canals. In the case of on-farm irrigation,
sprinkler and trickle irrigation 30% of wild and furrow irrigation.
Droughts may also result in environmental disasters through land degradation
and destruction of fauna and flora. The land becomes dry and wind may cause
erosion. Land would tend to become desert if necessary measures were taken.
Forestation is important as trees have capacity to hold the land and they have
capability to find water from deeper part of the land by means of their roots.
The need to have more water storage facilities is important to mitigate its
effects through their operation, that is, by storing water when available and
by using during the critical period when it is needed.
The other extreme meteorological event resulting excess of water cause another
disasters, that is, floods The average annual precipitation in small coastline
regions is 2,500 mm. in Turkey. As these figures indicate, floods are more
common in the coastal regions. Rivers in most European countries have regular
regimes. Rivers in Turkey have generally irregular regimes therefore natural
flow can not be utilized as usable water resources. Rivers in Turkey generally
have wild flows varying considerably throughout the year as well as in the course
of years. Floods are quite common in Turkey as in many countries in the world
such as Chine, India, and South American Countries.
By operating of water storage facilities to hold the amount of the water during
the extreme flow, flood hazards would be avoided if necessary number of the
dams were constructed on the river basin. as each
reservoir on the basin hold water so as to prevent hazards. But there are
basins in which there are not dams. In this case, it must be ensured that no
building, no roads, and no other obstruction are to
built on the discharge area of the rivers.
Due to fluctuations observed in the run-offs during seasons and during the
years, it is absolutely necessary for Turkey to construct dams so as to develop
its exploitable water potential.
Bibliography:
-Adem Ani Ünal, Chief of Foreign Relations, State Hydraulic Works (DSI) of General Directorate.
-Taner Ercömert, Deputy head of Dams and Hydropower Department, State Hydraulic
Works (DSI) of General Directorate.
-Prof. Dr. Veysel EROGLU,
Director General of DSI, Water World, Monthly
Magazine of State Hydraulic Works (DSI) of General
Directorate.
, pp: 42-47 “East Blacksea Region: Turkey’s landslide
and flood region, September, 2005.
-DSI 51st Anniversary, annual book of State Hydraulic
Works (DSI) of General Directorate.
Second Chart, pp: 15-26, “Land and Water
resources”, pp: 39-54, “irrigation”, 2005.
-Mümtaz Turfan, Chairman of
the TRCOLD, “Turkish Position Against WCD Report”, 2004.