ICZM with a focus on climate change rise in development
countries
Hernan Moreano: Vice-President of COASTMAN – Ecuador Foundation
Introduction
The low Guayas River basin (LGRB), located in the Southwest of Ecuador, is the most
productive area of Ecuador. It is an important area for agriculture and aquaculture,
which is the leading export products, together with oil. The contribution of this region
to the GDP is 20 billion US$. Farming and aquaculture provide direct and indirect
jobs to 3.2 million people on a total population of 12.1 million. The inhabitants of the
basin live mostly concentrated at Guayaquil (3 millions), which is Ecuador’s major
port and the economic capital. Besides agriculture, the area holds a mangrove
ecosystem of 120.000 ha and estuarine water bodies of 5100 km 2. These are
associated with the Guayas River and Estero Salado estuaries, connected with the
Gulf of Guayaquil through the Jambeli and El Morro channels.
The climate of Ecuador’s Coastal Zone is determined by the position of the Inter
Tropical Convergence Zone (ITCZ), the offshore water masses distribution and climate
variability events such as “El Niño” Southern Oscillation (ENSO). All of these are
responsible for flooding on the river basin areas and for sea level rise within the
estuaries. The last ENSO event of 1997 – 1998, for the period of 10 months, impacted
Equatorial Pacific coast, in this occasion the damages were valued at US$ 2.6 billions
in the entire coast. This is a rough estimate made by the Latin American and
Caribbean Economic Commission (CEPAL, 1998).
Climate Change (CC) is a risk for Ecuador coastal zones and especially for the LGRB.
For this reason we study the problems generated by CC, a final review of it was made
in 2006. Four Equatorial institutions carried out the study: “Instituto Oceanografico
de la Armada “(INOCAR), in charge of sea level rise studies in estuaries, “Instituto
Nacional de Pesca” (INP) who must focuses its work in impacts on mangrove
ecosystem, biodiversity and the shrimp industry, “Instituto Nacional de Meteorologia e
Hidrología” (INAMHI) that focuses the research on precipitation and assessment of
the low basin hydrographic system and “Instituto de Planificacion Urbana y Regional”
(IPUR) join to the Catholic University (UCSG) for social and economic impacts in the
study area.
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Problem definition ICZM
Under an Integrated Resources Management vision, an environment study, and the
related social and economic issues, as well as a vulnerability assessment study of the
Low Guayas River basin affected by climate change was conducted. In this study
precipitation, sea level rise and ENSO events were considered as a matter of Climate
Variability (CV) and were monitored periodically.
The goals of the study included
To assess the possible impacts of climate change at the present and future
situation of coastal resources and their consequences on economic and social
matters.
To identify possible attenuation measures and projects that could give way outs
with such measures.
To develop planning tools for Impact Assessment on long term changes of
resources and their use.
To contribute to establish the Ecuador Coastal Zone management institutional
structure.
To support Capacity building in Integrated Coastal Management.
To contribute to improve Ecuador National Communications on CC.
Approach
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The vulnerability assessment study was carried out all these years using the seven
steps as described in the Vulnerability Assessment of Coastal Areas to Sea Level Rise.
Steps 1 through 4 were made by the project coordinator and the working groups of
involved institutions. Additionally a series of workshops were organized to define the
boundaries of the study area, the possible climate scenarios for precipitation and sea
level rise, formulation of response strategies, results assessment and a long term
structure proposal to manage the Low Guayas River Basin.
A common methodology focused on natural and socio-economic system impact
assessment, as a consequence of the physical effects of sea level rise and on the effects
of response strategies was made. The vulnerability assessment began with a
delineation of the study area and specifications of sea level rise, boundary conditions.
Followed a study area inventory and the identification of relevant development
factors related to productivity activities, capital investment and natural values were
made.
After completing these three initial steps, a physical change assessment and the
natural system response were determined; this included morphological development
of the shore line, water level and changes in salinity. Afterward, the response options
were formulated, estimating their cost and effects, all this, considering scenarios that
represent cases showing the cost of the response options in each economic scenario
(with and without development). The vulnerability assessment ended assessing the
susceptibility of changes, forced by sea level rise and related socio-economic impacts,
followed by actions to develop a long term basin management plant, based on
integration and participatory decision making.
Results of the vulnerability assessment
Guayas and Estero Salado estuaries were selected as study areas due to its sensitivity
to sea level rise. Impacts of flooding already undergo on this area, could increase in
the future as a result of sea level rise and changes in precipitation. The study area
perimeter is 630 km and encircles an area of nearly 15.000 km2 that holds 200.000
ha of banana, rice and sugar cane farming fields. The zone has a population of 3.4
million people, mostly concentrated at Guayaquil, which is a city port, located at the
upper branches of the Guayas River and Estero Salado estuaries where a series of
islands and archipelagos are distributed nearby; most of them are covered by
mangrove forest and shrimps ponds. On the southern part are located Machala and
Puerto Bolivar, the main city and port, respectively.
Estuarine waters are tide driven and their volume depends on ocean currents traits,
mainly at the eastern Pacific, as well as on precipitation, fresh water river inputs,
caused by the southward motion of the ITCZ, and by warm ocean water masses
driven by surface currents or by the ENSO event.
The geometry of these estuarine systems and the differences in phases with sea level
make a complicated pattern of circulation, especially near the mouth area where
both estuaries are connected. Through Guayas River estuary, salinity gradients are
noticeable, since fresh water inflow fluctuates during the seasons. The maximum
range of the salinity intrusion is as far as Guayaquil is located; but it does not
penetrate further because of Daule River permanent flow, which is controlled by the
Daule-Peripa Dam, in the north part. Vertical gradients are almost insignificant and
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both estuaries fall in categories 1a and 1b, in the Hansen and Rattray (1996)
circulation and stratification diagram.
The tidal prisms for the Guayas and Estero Salado estuaries are 4.4 billions, and 1.2
billions cubic meters respectively. The flushing time for the Guayas Estuary is between
8 to 13 days and could be less in periods of high river flows associated with El Niño. In
contrast, the Estero Salado upper part, located at the west of Guayaquil, does not
have fresh water inflow and its flushing time is longer than this of Guayas. Going
southward and close to the mouth, the water exchange with the ocean and with the
other estuary increases, consequently the flushing time decreases.
All three hydrographic systems are responsible for sediment transport and fresh water
inflow into the study area.
The economic situation
The economy of Ecuador is marked by a huge external debt of US$ 13000 millions
dollars, an annual budget with lack of resources to invest in productive sectors. The
economy is characterized by a low foreign investment, lack of economical, legal and
political systems guarantees. The economy manages high inflation and interest rates.
At nowadays the country unemployment is about 10.3%.
Two sectors are responsible for one third of exports incomes; they are the agriculture
and shrimps farming, both of them taking place in the study area. The population
has a growth rate near 2.2% per year.
Climate Scenarios
Several climate scenarios were established for 2010
Scenarios
Basic (SLR 0)
Moderated
(SLR 1)
Severe (SLR 2)
Conditions
No changes in sea level, air and ocean surface temperatures and
precipitation.
Sea level rise 0.3 m, with an increase of 1°C in air temperature,
Sea Surface temperature (SST) anomalies less than 1°C and a 15%
reduction in precipitation.
Sea level rise of 1.0 m, with an increase of 2°C in air temperature.
SST anomalies over 2°C and a 20% increase in precipitation.
As the study area is not affected by ocean storms, hurricanes and tornados, the
climate scenarios do not consider data related to these events.
Outputs of most Global Climate Models (GCM) are in Celsius degrees of air
temperature variation and percentage of precipitation below or above average.
Unfortunately, climate in the global context and particularly on Ecuador’s coastal
zone is not only related to changes in the atmosphere, but also to changes in the
offshore water masses driven by surface currents. These in turn are coupled to the
wind driven circulation patterns on the Pacific Ocean.
The proposed INAMHI scenarios were as follows (values for 2010 compared to 1998):
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Scenarios
1
2
3
4
Air temperature
+ 1°C
+ 2°C
+ 1°C
+ 2°C
Precipitation
- 15%
- 20%
+ 20%
- 15%
Year: 2006.
The working group of experts agreed that scenario 1 matches with the moderate
scenario for the Vulnerability assessment study, assuming an increase of water
transport of the Humboldt coastal current but keeping SST anomalies < 1oC, air
temperatures will increase by 1°C, precipitation will be less than overage by 15% and
there will be and increase of sea level of 0.3 m. Meanwhile scenario 2 matches with
the severe one, assuming an offshore warm water mass which source is the Panama
basin and it is driven southward by El Niño current; SST anomalies rise over 2.5oC, air
temperature will increase at least by 2oC, precipitation will be above overage by 20%
and sea level rise will be 1.0. Scenarios 3 and 4 are far away from reality because
with a cool ocean is impossible to have a 20% increase in precipitation and with a
warm ocean is impossible to expect a decrease in rainfall.
Capital lost
Capital lost, at risk and at change was considered for each of the impact zones for the
1998 and 2010 scenarios. Capital lost include all flooded land and coastal habitats
such as mangroves, shrimp ponds, banana, rice and sugar cane plantations, beaches
and urban areas of Guayaquil, Machala and Puerto Bolivar. Losses for SLR 1 are in
the order of 10% to 14% of GDP, but for SLR 2, they go up to 12,5% and 18.5% for 1998
and 2010 respectively.
Major loses are from mangroves and sugar cane plantations and associated industry.
Mangrove will almost disappear in the SLR2 scenario, this represents a loss of over one
billion US$ without considering associated biodiversity, CO2, fixation and the role of
this forest in the estuarine ecosystem. Although, the response strategy cost is high, it
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could be distributed through time, which allows for the investment to keep this
natural system alive.
Policy implications
To reduce the vulnerability of the LGRB to climate change must be build dams,
irrigations and bypass channels, projects of water, hydroelectric plants and drainage
systems. Most of these strategies are being designed by CEDEGE and PREDESUR*
(CEDEGE 2004).
During the last 10 years CEDEGE had completed the following projects:
Bypasses of the Bulu Bulu and Chimbo rivers,
Irrigation and drainage system of the Catarama River,
The transfer of water from the Daule River to the Peninsula de Santa Elena.
The Daule Peripa to La Esperanza and Poza Onda project,
The 210 MWatt hydroelectric plant.
PREDESUR have completed:
Various drainage and irrigation projects related with the Marcabeli Dam in El Oro
province. The infrastructure will reduce the risk of the study area to climate change
and climate variability events like “El Niño”.
Conclusions:
The vulnerability assessment showed the vulnerability of the LGRB to climate change
and climate variability. The worst case scenario (SLR2) indicates that capital at risk
and capital lost together will be three billion US$. (to the next 2010). The cost –
benefit relation is favorable to implement the measures now, but, the cost will
increase substantially high if they will be implemented for 2010. The main constrain
for implementing response strategies for sea level rise and precipitation changes is
that the economy of Ecuador can not bear the investments.
References
CEDEGE (2004) General Plan for development of the LGRB
INOCAR (2005) Sea level rise
IPUR (2001) Socio economical Study
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