Integrated Watershed Management, IWSM in the Limelight: A Genuine Development of Rural Infrastructure for the Rural poor or A Trending Globalization phenomenon or, even a nightmare?
As a soil and water conservationist,
I am continuously involved in, and
continuously in strive to be informed (from literature, discussions and mass media broadcasts,
etc...).Besides, I had a number of business-like short acquaintances in the
recent past with number of professionals working in the field of IWSM or in
areas associated with it in our region. Through my works as a researcher, and
professional who travels, I have come to see
the various faces of environmental projects of local, regional and
international nature.. To my surprise, I continuously heard some comments and
arguments which are ; and in fact like self-centred opinions far from the
scientific principles and practices of the subject area. As a result, I was
initiated to bring the issues to the limelight for all of us to learn from each
other. To break the ice, I thought I had to go back to the drawing board. As a
consequence,
- I have put down some of the questions which necessitate a serious consideration.(in this Issue)
- Remembered the drought and famines in the 70’s and 80’s in Ethiopia which triggered massive food Aid programmes; and consequently Watershed programmes as we know them.
- An agonizing situation of recent trends in inland water bodies in Ethiopia as a crude example of the magnitude of the problem (water body pollution Biota degradation, loss of livelihoods, etc..) .(in this Issue)
- Recent talks about the Climate Resilience in the Sahel region: saving Lake Chad, etc.. (Which had already shrank from 25km2 to 2kms2)
Please forgive me for the bold
language, and opinions, if any, that are unpleasant and unpalatable. They are not
intentionally aimed otherwise, except to provoke/stir up discussions.
As they say ‘’ an educated person is measured by the power
of willingness and ability he possesses to listen to opposing arguments.’’
Please see through and comment.
The full essay is due soon.....
1. How much simplification /to allow/tolerate for mass mobilization and/or to satisfy the ego of over ambitious plans
1.1 What is your overall objective of the IWSM?
a. To solve real catchment
scale problems of degradation/loss of rural livelihoods
b. To distribute food for
drought and famine victims through ‘environmental protection’ labour rather
than free handouts
c. To distribute cash so as
to create employment for destitute rural population /for security reasons?/
d. For security reasons to curtail militancy
e. To gain acceptance to spread out our convictions/ways of thinking / opinion/
as a lubricant to be heard/politics,religion.etc../
1.2 Technical objectives
a. To improve/sustain
farming livelihoods by increasing productivity, reducing erosion, production of
fodder and tree plantations, community water supply, and irrigation/land
development,....................
b. To Increase water yield of the catchment/
c. To reduce sediment load
from the catchment/mainly where?
Cultivated land, gully
control, land slides. etc. mining pits
(quarry.
d. To solve energy and
construction materials needs through Firewood, and plantations
e. To combat desertification
and create climate resilience
f.
To
reduce water body pollution. If so how to control/reduce rural
Sewage/settlement and
livestock/; and village solid waste.
g. Manage aid/loans of
natural disasters
1. 3 Design and implementation boundary
a. Catchment scale; small
watersheds
b. Administrative boundary
i.
Woreda
of your choice/ Farmers of your choice/
ii.
willing
farmers who present Petition of help
c. Undertake watershed study
d. Where to start
e. Approaches and methods of
study and project evaluation
i.
If
to dispose excess water, Grassed waterways atleast a rainy season earlier; or
after terraces are constructed
1.4 Who to work with
- How do you select your professionals/experts and specialists?(Through contacts, recommendation of clients institution; political influence,...)
- Do you need in-country /Local/ expertise; and experience
- Do you recruit on equal opportunity basis? /No nepotism, No discrimination/
- Tolerate new ideas and ways of doing things:Accept Who can think outside the box -or/they are not needed?
- You prefer followers who are used to performing when, and as told.
1.5 Catchment /watershed/ study
The study
Base data collection
Approaches and methods
Problem assessment;
quantification
Pilot Trial studies
Supported by local
research data
Base Maps
Contour map-Slope
class-LCC-LU-proposed conservation design
NOTE:-only
started very recently (in the last decade/10 years/) after serious
arguments/collisions with consultants for years in oromia
Mechanical measures –
for what?
Water removal/or water
harvesting
Biological measures
-Agroforestry
Vegetal Barrier strips
for benching effect
Terrace and check damns design
specifications
How much RO?
What formula to employ? blanket
recommendations?
Mannings’ Formula & roughness coefficient-used
when, and under what conditions?
Non-submerged flow
conditions? Run off from mountainous catchment??
Note:-A
MoWR consultant study(Expatriate) proposed use of it for... to design waterway canals for control of DireDawa
flood(floods carrying large boulders...
Examples of some of the
questions to be asked in design
considerations for terraces, and check dams are given below!!! (Chapter
3.3)
2. Tugging SWC/SLM out of its comfort zone of the Science and Technology domain: Historical & Emerging features
Preamble
Right from the start of the SWC
programmes following the 1974 famines, there has been a strong argument about
the establishing institutional belief that treated SWC as an art and not a science,
and technology. SWC was taken as a mass mobilization activity requiring no
rigorous planning and design: as simple as planting trees; and blanket
recommendations of SWC measures such as terraces was taken as panacea.
Besides, it was taken not as a useful and indispensable
science by its own right, but as a surrogate of expatriate solutions for
droughts and famine. Thus, In the early years,
FFW. And FFC took the centre stage of the watershed development
programmes. Forestry of exotic trees everywhere; terracing of hillslopes; Area
closures and miniature checkdams put on gully beds became the core activity. The
projects followed the main asphalt roads leading to major cities with
relatively good hotels and recreational facilities. What a weekend for the
visitors!!
Road side plantings for promotional/exhibition
purposes were prominent. Hill slopes along all weather-road/accessible areas
were targeted. Their aim was propaganda and a receipt to settle finances as
they were later called ‘political forests’.
3. How much of oneself should we sacrifice to get help to help ourselves?
3.1 Contracting out core Activities
In this Current era of globalization
and the overriding neo-liberal thinking wrongfully understood by most of our
leaders in the developing countries, It has become the trend to see some major
core activities of the government being contracted/leased out to private
companies. Consequently, aspects of Basic services to the society/nation/ such
as Education, Natural Resources protection, health, etc are largely managed by
institutionalized non-governmental actors put in governmental channels.
May be, it is the ‘modern&
acceptable’ way of capacity building; I don’t know. What I definitely know and
argue about is the need for local management, expertise ,and experience taking
the leading role; and supported by others, if need be.
3. How much ’ferenjization’ should we allow to secure loans/aids and appease donors/globalization
3.1 Running Programmes, and Projects; Managing Funds
One of the recent trends in
Developing countries is that donors are becoming more reluctant to fund
research and natural resources development projects as usual. They are
overtaking the management of funds and projects through International
organization representatives, or newly created “NGO’ like organizations.
It is undeniable that we , as one of
the poorest nation on the globe, and a
developing country absolutely need the knowledge transfer and experience
sharing from expatriates..These are in distinct and selected areas requiring
the state of the art science and technology..Nonetheless, we ought to be smart
enough to learn from our colleagues in the developing countries who have preceded
us in pursing this goal to exploit the ever diminishing cooperation and help on
equal footings with dignity and respect. Inclusion of employment of foreigners
doesn’t have to be a lubricant for every fund obtained In areas we are capable
of The accords ought to result in us benefitting from proven ways and methods
of doing things. We have to identify our
needs, prior to any act of importing
even for practically proven experience
and skills.
Furthermore, one of the issues which
is always mentioned is that recipient countries are corrupt...Aid will not
reach targeted communities...Come on guys! Does corruption have colour? If it
does, I think, it is not necessary dark..it is probably the ‘white elephant’
who needs a lot for face lifting.
Besides, we need to lead our
national programmes of environment and development. We should be the ultimate
ones to determine our fate. We should own our projects and programmes. Do we
really need expatriates to manage the Funds? Even though, a helping hand as knowledge
and experience sharing is not bad; I don’t necessarily think that we be
subordinate in the process. We can make reasonable decisions on what is ought
to be done, and where it should be? We have the professional capacity and ability
to run our affairs. In this case, to select
a project area of critical need with the maximum possible results is not beyond
our reach.
3.2 Temperate climate Experience
Temperate climate with its Rainfall
intensity and pattern soil types, flat topography and produces if completely
different from the tro[ics.This is more so in the field of soil& water
conservation.
Do we need temperate climate Land
use and soil & water conservation experience then?
Can we use western USDA Method of LCC,
and LU Planning?
What will happen to the tree and
cash crops grown on hill slopes(>12% maximum in USDA classification)
Modify as in any other tropical land
use and agricultural system?
Available alternatives: Sheng’s
treatment oriented LCC
3.3 Examples of design considerations
3.3.1 Checkdams
Anchor/Posts/footing-0.6m
Wing walls/ Side locks/
Side bank modification & bed
Slope stabilization
Aprons above and below dam axis –
tree branches?
Artificial/natural re-vegetation of
gullies
Check dams are first line of defence
to be reinforced by vegetation
Overflow/crest weir
Flow diversion upslope if possible.
3.3.2 Terraces
Terraces/
bench/or channel? stone
or earthen?
For bench Terraces
Physical construction/or
Development of Bench Terraces
stage wise development from barrier
strips/grass strips /trash lines/infiltration zones/agro-forestry?
Level or drainage
terraces?
Determine
drainage/absorptive type based on Rainfall /or what parameter?
Note:
early this Ethiopian year a senior national SLM specialist suggested and argued
that terraces are designed as level/or graded based on soil moisture content
Use contour guidelines and pegs
Contour guidelines smoothening to
get smooth curves?
If graded terraces-
Bed slopes based on soil
type
Compaction same along
flow gradient
Continuity of flow-take
it where?
collect runoff in volume,
and velocity(high energy)and release it somewhere-like highway roadside ditches?
Integration of mechanical measures With
other farm activities eg paths and roads/livestock trails
Stone terraces
Why stone?
Type of stone
Put flat bottom for stable
gravity
Annexes
1. Characteristics
of some Reservoirs in Ethiopia: Recent Status of Representative old Dams (Ligdi,
2010a)
The Aba Samuel Dam
One of
the oldest and abandoned storage reservoir constructed on the Akaki River at
Akaki-South of Addis Ababa, is the Aba Samuel Dam. It was constructed in 1939
for hydro-power production. Reservoir sedimentation survey was carried out in
1983 after 44 years of service & the average specific sediment yield was
estimated at 445 t'km2/yr.). Besides the
non point source pollutants from agricultural sediments, the Aba Samuel
reservoir has long been entertaining the sediment yields from construction and
mining sites in its watershed in and
around the city. Furthermore, the dam receives point source pollutants
in the form of urban waste, domestic (raw) sewage and factory effluents and
contaminants from the tributaries of Akaki River which drain the city of Addis
Ababa. As a result, it is polluted with eutrophication and signs of
cynobacterial toxicity and abandoned long ago.
The
Koka Dam
The
Koka reservoir has been created as a result of the construction of the Koka Dam
in 1959 for developing hydroelectric power. Awash and Modjo rivers which are
heavily laden with sediments during the flood season are the two main rivers
which flow to the reservoir. According to a recent bathymetric survey, the
capacity of Koka reservoir has been reduced from 1667Mm3 in 1959 to 1186 Mm3 in
1998 .The loss on total capacity over 39 years is 481 Mm3 i.e. 28.8% of the
total storage volume. The average annual loss of capacity is 0.74% and annual
silting rate is 12.32 Mm3. It was found that about 397.1 Mm3 (i.e. .82.6%) has
been deposited in the active storage. The displacement of 481 Mm3 of
water per year by sediments translated to energy loss and the
subsequent output lost (by manufacturing sector) will be tremendous. The sediment deposits in the
reservoir including the year 2000 have grown to be a serious threat to the
intakes at the dam and have already reduced the useful storage volume by
30.3%.(Haile,2001) .In addition
to sedimentation the lake is affected with incoming factory effluents and
contaminants from the tributaries leading to eutrophication and signs of
cynobacterial toxicity.
The Gefersa Dam
The
Geffersa dam with a catchment area is 55 km2 was constructed in 1955
at some 15 kms. west of the city, as a source of Addis Ababa city water supply.
Over and above lose of capacity, the increasing sediment loads and siltation is
causing water quality deteriorations and initiating costly additional water
purification requirements further exacerbating the task to satisfy the
skyrocketing demands of the city. To this end, it has gone through various improvements
and upgrading including construction of series of additional dams built upslope
,in addition to raising the dam height during its recent
renovation. Currently, Geffersa III (since 1986) dam acts a sediment
trap for Geffersa
I and II.
2. Recent changes and Emerging trends in Inland Water Bodies in Ethiopia
A. Causes of recent changes in Rift valley
lakes as summarized by Ayenew
(2008) are:
A. Anthropogenic- Excessive water use, Mismanagement
B. Natural- Climate change- ( Global / local
),and
C. Neo-tectonics.
He also mentioned the disturbing
recent changes in Rift valley lakes as
·
Lakes
show contrasting temporal variations in stage and size .
· Complete
drying up of lakes.(E.g. Haromaya in the
Eastern Hararghe highlands)
·
Disappearance
of springs/swamps/ connected to the lakes
B. Major emerging changes in Ethiopian Lakes
(Ayenew 2007, Ligdi 2008,2010a)
- Lakes show contrasting temporal variations in stage and size . Some are expanding eg. Lake Beseka (areal), Lake Hawassa (Rising levels)); and some are shrinking (e.g..Abiata and Ziway)
- Complete drying up of lakes.(E.g. Lange , Kersa, and recently Adele and Haromaya in the Eastern Hararghe highlands)
- Disappearance of springs/swamps/ connected to the lakes ( E.g. wetland degradation)
- Change in the biodiversity (biota degradation, decline in fishery Stocks ,etc…)
- Change in constituents and water quality deterioration (sedimentation, eutrophication, and signs of cynobacterial toxicity
C. The main
anthropogenic effects on waterbodies (Ligdi,2008, 2010a)
- Habitat & Species degradation (biota in the form of riparian vegetation, ecotones, wetlands, etc...; ,fisheries; other biodiversity);
- Water level flactuations (diversion of tributaries, excessive withdrawals, seasonal flooding, etc...)
- Sedimentation from non point source pollution ( causing rising water levels, flooding, storage loss, water quality deterioration & eutrophication) ; plus
- point source pollution from domestic waste(urban + rural), urban (and settlement+livestock) sewage,and industrial effluent leading to
- Eutrophication and Cynnobacterial toxicity due to incoming high loads of Nitrogen & Phosphorus and toxic metals [Aba Samuel, Koka, Awassa, Tana]
D. The agonizing case
of Lake Haromaya (Ligdi,2010a)
One
of the best cases in point to show the recent trends in inland water bodies in
Ethiopia is the drying up and sudden
disappearance of Lakes in the eastern Hararghe highlands in Oromia.. There were
around 3 other lakes which completely dried up in the Eastern Hararge Highlands
in Oromia in the last half century or so. Lake Haromaya is the recent
victim of the phenomenon resulting in
complete drying up since around 2004.
The Present Day Lake Haramaya : From a Water Source to a Grazing
Land.
The Haromaya lake used
to cover a surface area of 472 hectares and received a mean annual rainfall of
723 mm. The Haromaya lake was once the largest source of fresh water and
for over 40 years( 1961 – 2004) ,
it had provided fresh water for domestic(human and Livestock) water supply for the Haromaya
and Harar towns.It had also supplied water for irrigation, and reently for industrial
uses in and around the Haromaya and Harar towns and the vicinity.
Furthermore, it had supported ecological life to fishes, and other species.,
besides being a drinking source and feeding place to birds and
animals.
Some
15 years ago, the lake had a maximum and mean depth of 8 m and 3.13 m respectively
covering a surface area of 47.9 km2. Now, the lake is completely dry
since around 2004. Groundwater is on average 3 meters below the dried lake bed.
Regrettably, the present day Lake Haramaya has changed from a water source to a
grazing land.
A
multitude of factors may have contributed to the drying up of the lake which
requires serious investigations. Ecological, hydrological and Geological
(fructure) causes have been postulated since.
Nevertheless, the drying up of the lake has largely affected domestic
and industrial water uses, recreation,
fisheries and agricultural activities.
3.` Strategies for Dealing with Reservoir Sedimentation
The following four main strategies are
recommended to reduce sedimentation problem in storage reservoirs (Basson &
Rooseboom. (1996) mentioned in Haile,(2001))
1. Minimize sediment loads entering the reservoir
through;
Soil
and water conservation programmes (Integrated Watershed Management, IWRM); Upstream trapping of sediment (debris dams or
vegetation screens); and Bypassing of high
sediment loads (bypass tunnel or channel, or off-stream storage that allows floods
to be passed in the river).
2.
Minimize deposition in reservoirs through;
Drawdown
and sluicing: passing sediment-laden flows through the reservoir by means
of drawing down the water level; and venting density current
3. Removal
of accumulated sediment deposits through;
Flushing by drawing down the water
level , in many cases, emptying the reservoir during
floods or in the rainy season; Mechanical excavation or dredging; Conventional hydraulic dredging; and Hydraulic dredging by use of gravity
(Transport of sediment in pipeline
or by free surface flow in channels or tunnels).
4.
Compensating for reservoir sedimentation;
Maintain long-term storage capacity
by raising the dam; Abandon or decommission the
silted reservoir and construct a new reservoir; and Import water from elsewhere.
4. Conventional hydro-technical technologies for reduction of sediment yield (Gogus, 2007)
1.
Vegetative screens
Vegetation normally seeds on exposed
delta deposits of reservoirs to form natural
vegetative screens which
reduce inflow velocities and increase the roughness
coefficients, encouraging deposition above
the reservoir crest elevation within the
reservoir basin or immediately upstream.
2. Watershed structures
Several types of structures may be built in
a watershed for the specific purpose of
reducing sediment yield to a reservoir.
These include such structures as sedimentation
basins to trap sediment below eroding areas
and erosion control structures to halt the
production of sediment.
The reduction of channel erosion
normally requires a structure. In a watershed, where
the primary source of sediment is derived
from channel erosion, installation of control structures
may have an appreciable effect in reducing sediment yield to a reservoir.
Such structures include drop inlets and
chutes for reduction of gully erosion, stream-
bank revetment to reduce stream-bank
erosion, and sill or drop structures for
stream bed stabilization.
3. Watershed land -treatment measures
Land
treatment measures provide an effective and economical means of reducing
erosion and sediment yield where the
primary source of sediment is sheet (Raindrop, Rill and
Inter-rill) erosion. These measures include soil improvement, proper tillage
methods, strip cropping, terracing, and crop rotations and
others.
4. Control of wind erosion
Wind
erosion is a serious problem in areas of low precipitation, frequent drought,
and
where temperatures, evaporation, and wind
speeds are high.
5. Summary of available information (figures and values) on physical description and water quality parameters of Lake Tana.
NOTE
:-The available information (figures and values) on the physical
description of the lake (Length, Area, Volume , etc…); and water quality
parameters given in previous study & research documents differ & are
not consistent through. Based on a literature
review, summary of the comparisons of data on the Physiography of the Lake
(Table I) and some Selected Physical
and Chemical Water Quality Results from Previous Works is presented in Table
II.
Table I: Summary of Comparison of various
data and figures on the description of the
Physiography of Lake Tana (Sub-basin) based on Results
from Previous Works.
Parameters
|
Values
|
Date of
Sampling
|
Reference
|
||
· Surface
Area of Lake Tana (km2)
|
3000 – 3500
|
Late 1990 are...
|
BCEOM (1998)
|
||
3150
|
2003
|
E. Dejen (2003)
|
|||
3500
|
Ashine
(1998),
|
||||
3200
|
Wudneh
(1998),
|
||||
3675
|
Oduola
(2003)
|
||||
3600
|
www.worldlakes.org (2004).
|
||||
3050
|
estimated
|
Tesfahun &
Demisse(2005).
|
|||
85km wide x 65km
Long
84
long X 66km wide
|
Approximate
|
Tesfahun &
Demisse(2005).
Setegn (2008)
|
|||
· Catchments
Area of Lake Tana (km2)
|
15000 – 16500
|
1987 and 1997
|
BCEOM
|
||
16500
|
2003
|
E. Dejen 2003
|
|||
15054
15096
|
(Tesfahun &
Demisse(2005).
Setegn (2008)
|
||||
· Average depth (m)
|
8 – 9
|
Late 1990's
|
BCEOM
|
||
8 – 9
|
2003
|
E. Dejen 2003
|
|||
· Max.
Depth (m)
|
14
|
Late 1990's
|
BCEOM
|
||
14
|
2003
|
E. Dejen 2003
|
|||
15
|
2008
|
Setegn (2008)
|
|||
Storage
Volume (BCM)
|
28 - 29.2
|
1997
|
BCEOM
|
||
28
|
1988
|
Wassie, 2005
|
|||
· Shore
line length (km)
|
-
|
-
|
BCEOM
|
||
385
|
1976
|
Wassie, 2005
|
|||
· Altitude
(masl)
|
1786
|
Late 1990'
|
BCEOM
|
||
1830
|
2003
|
E. Dejen 2003
|
|||
1800
|
2008
|
Setegn (2008)
|
|||
1783.52
|
Datum (hydrology
Department)
|
MoWR
(Personal
communication)
|
|||
· Annual
Soil loss in the Lake Tana Sub basin (Tone/ha)
|
30 – 100
|
1980's and 1990's
|
BCEOM, 1908
|
||
31 – 50
|
2001
|
E. Dejen 2003
|
|||
Data Source:- Modified from MoWR (2008);
Ligdi (2008, 2010c)
Table II: Summary of Comparison of various
data and figures of some Selected Physical and
Chemical Water Quality Parameter Results of Lake Tana from
Previous Works.
Parameters
|
Measured
Figures/values
|
Measurement
Year
|
Source
/
Reported
by
|
·
PH Values
|
7.50
- 8.87
|
1940
and 1997
|
BCEOM
|
6.8
- 8.3
|
2004
|
Wassie,
2005
|
|
·
EC (µS/cm)
|
105
– 234
|
1997
|
BCEOM
|
115
– 148
|
2004
|
Wassie,
2005
|
|
·
Dissolved oxygen (mg/l)
|
3.3
- 10.8
|
1997
|
BCEOM
|
5.9
- 7.3
|
2000
– 2002
|
E.
Dejen 2003
|
|
·
Chlorophyll 'a' (mg/m3)
|
3.7
- 6.2
|
1986
and 1988
|
BCEOM
|
3.4
- 12.9
|
2000
– 2002
|
E.
Dejen 2003
|
|
·
Biomass (mg C/m3)
|
129
|
1997
|
BCEOM
|
·
Transparency (cm)
|
31
– 182
|
1997
|
BCEOM
|
·
Temperature (°c)
|
18.3
- 26.2
|
1997
|
BCEOM
|
20
-27
|
2000
– 2002
|
E.
Dejen 2003
|
·
TDS (mg/l)
|
151
– 174
|
1925
and 1940
|
BCEOM
|
148
-178
|
2000
– 2002
|
E.
Dejen 2003
|
·
Calcium (mg/l)
|
18
– 27
|
1925
and 1940
|
BCEOM
|
·
Magnesium (mg/l)
|
9
– 10
|
1925,
1940 and 1995
|
BCEOM
|
·
Chloride (mg/l)
|
8
|
1925
and 1940
|
BCEOM
|
·
Silica (mg/l)
|
22
|
1940
|
BCEOM
|
·
Hardness (mg/l) as CaCo3)
|
85
|
1995
|
BCEOM
|
·
Total Alkalinity (mg/l)
|
104
|
1940
|
BCEOM
|
·
Turbidity (NTU)
|
-
|
-
|
-
|
13
– 85
|
2000
- 2002
|
E.
Dejen 2003
|
·
Annual Soil loss in the
Lake Tana Sub basin (Tone/ha)
|
30
– 100
|
1980's
and 1990's
|
BCEOM,
1908
|
31
– 50
|
2001
|
E.
Dejen 2003
|
Data Source:- MoWR,(2008); Ligdi (2008,2010c)
SOURCE:
Ligdi,E.E., (2011). Ecohydrology & Sustainable Sediment Management in Inland water bodies in Ethiopia. :
A Review with a case Study Site at Lake Tana in the Upper Blue Nile (Abbay) Basin in Ethiopia..A case
Study Report.UNESCO-IHP;FRIEND/Nile Project, Phase II;Eco-Hydrology Component. Addis Ababa, Ethiopia
A Review with a case Study Site at Lake Tana in the Upper Blue Nile (Abbay) Basin in Ethiopia..A case
Study Report.UNESCO-IHP;FRIEND/Nile Project, Phase II;Eco-Hydrology Component. Addis Ababa, Ethiopia
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