5 research outputs found
Macro-catchment rainwater harvesting systems: Challenges and opportunities to access runoff
Journal of Animal & Plant Sciences, 2010. Vol. 7(2): 789- 800.Rainwater harvesting (RWH) is the process of interception and concentration of runoff and
its subsequent storage either in soil for direct use by plants or in reservoirs for later
application when needed to mitigate dry spells. RWH varies from macro to micro to in-situ
systems based on the size of the catchments and runoff transfer distances. Macro RWH
systems with or without storage has shown to be more applicable among communities as
compared to micro catchments RWH systems. The study aimed at looking on the
complexity of biophysical and social economic factors affecting potentiality of the use of
runoff harvested from macro catchment. The results of the study identified two broad
categories of constraints which are hydro-climatic and management of harvested runoff at
the farm level scale. The hydro-climatic challenges are more related to climate while
management looks on the transaction cost reflected on the maintenance of the systems,
equitable access to runoff and related resources. Results indicated that during the short rain
season, the seasonal rainfall amount received does not meet maize water requirements,
hence requires supplementary irrigation water to mitigate dry spells. Other biophysical
challenge is the change of the runoff conveyance channels due to erosion and deposition.
The results showed that fields in close proximity to runoff sources can receive from 70
m3/ha to 300 m3/ha of runoff and the crop yields on these fields that received extra water
from external catchments (macro RWH), increased by more than 120% as compared to
fields that received rainfall only. The result also showed that the amount received in the field
is not the only factor that can contribute to the water use efficiency but also depends on infield
management. The study therefore, recommends that the modeling of macro
catchments RWH models should not only deal with hydro-climatic challenges but also
looks on the social economic for efficient and equitable distributions of resources runoff
from macro-catchment
Macro-catchment rainwater harvesting systems: Challenges and opportunities to access runoff
Journal of Animal & Plant Sciences, 2010. Vol. 7(2): 789- 800.Rainwater harvesting (RWH) is the process of interception and concentration of runoff and
its subsequent storage either in soil for direct use by plants or in reservoirs for later
application when needed to mitigate dry spells. RWH varies from macro to micro to in-situ
systems based on the size of the catchments and runoff transfer distances. Macro RWH
systems with or without storage has shown to be more applicable among communities as
compared to micro catchments RWH systems. The study aimed at looking on the
complexity of biophysical and social economic factors affecting potentiality of the use of
runoff harvested from macro catchment. The results of the study identified two broad
categories of constraints which are hydro-climatic and management of harvested runoff at
the farm level scale. The hydro-climatic challenges are more related to climate while
management looks on the transaction cost reflected on the maintenance of the systems,
equitable access to runoff and related resources. Results indicated that during the short rain
season, the seasonal rainfall amount received does not meet maize water requirements,
hence requires supplementary irrigation water to mitigate dry spells. Other biophysical
challenge is the change of the runoff conveyance channels due to erosion and deposition.
The results showed that fields in close proximity to runoff sources can receive from 70
m3/ha to 300 m3/ha of runoff and the crop yields on these fields that received extra water
from external catchments (macro RWH), increased by more than 120% as compared to
fields that received rainfall only. The result also showed that the amount received in the field
is not the only factor that can contribute to the water use efficiency but also depends on infield
management. The study therefore, recommends that the modeling of macro
catchments RWH models should not only deal with hydro-climatic challenges but also
looks on the social economic for efficient and equitable distributions of resources runoff
from macro-catchment
DEVELOPING IMPROVED DRYLAND CROPPING SYSTEMS FOR MAIZE IN SEMI-ARID TANZANIA. PART 1: EXPERIMENTAL EVIDENCE FOR THE BENEFITS OF RAINWATER HARVESTING
DEVELOPING IMPROVED DRYLAND CROPPING SYSTEMS FOR MAIZE IN SEMI-ARID TANZANIA. PART II. USE OF A MODEL TO EXTRAPOLATE AND ADD VALUE TO EXPERIMENTAL RESULTS
Integrated assessment of climate change impacts and adaptation in agriculture: the case study of the Wami River Sub-basin, Tanzania
A Book chapter, Climate Variability and Change in Africa, Sustainable
Development Goals Series, 115-136 pp.This study evaluates the impacts of climate
change and an adaptation strategy on agricul-
ture in the Wami River sub-basin in Tanzania.
This study uses the Agricultural Model
Improvement and Inter-comparison Project
(AgMIP) framework that integrates climate,
crops and economic models and data using a
novel multi-model approach for impact assess-
ment of agricultural systems under current and future conditions. This study uses five Global
Circulation Models (GCMs) from the fifth
phase of the Coupled Model Inter-comparison
Project (CMIP5), two crop simulation models,
and one economic impact assessment model. In
this study, a representative agricultural path-
ways (RAP) that characterises future condi-
tions following ‘business-as-usual’ trends was
developed and used to model future agricul-
tural systems in the Wami River sub-basin.
Results show that by mid-century, the maxi-
mum and minimum temperatures will increase
by 1.8–4.1 °C and 1.4–4.6 °C, respectively.
Rainfall is predicted to be variable with some
places projected to increase by 12%, while in
other areas it is projected to decrease by 14–
28%. Maize yields under these conditions are
projected to decrease by 5.3–40.7%. Results
show that under current conditions, 50–60% of
farm households are vulnerable to losses due to
climate change. The impacts of climate change
on poverty and per capita income are also
projected to be negative. Under the current
production system, poverty rates were pro-
jected to increase by 0.8–15.3% and per-capita
income to drop by 1.3–7.5%. Future
socio-economic conditions and prices offset
the negative impacts of climate change. Under
future conditions, the proportion of households
vulnerable to loss is estimated to range from 25
to 50%. Per-capita income and poverty rates are
expected to improve under the future climate
change conditions. Poverty rates would
decrease between 1.9 and 11.2% and income
per-capita would increase between 2.6 and
18.5%. The proposed future adaptation pack-
age will further improve household liveli-
hoods. This integrated assessment of climate
change projections using the improved meth-
ods and tools developed by AgMIP has con-
tributed to a better understanding of climate
change and adaptation impacts in a holistic
manner