01
Project Setting
Geographical setting, geology, topography, soils, climate and the physical suitability of the Hare River command area for irrigation development.
Original engineering study preserved · Modern reassessment active
The HARE
Project
Irrigation Engineering · Hydrology · Hydraulic Structures
A detailed 1995 irrigation-engineering study of the Hare River area near Arba Minch, preserving the original design logic for irrigation demand, hydrology, canals, regulators, diversion headworks and associated hydraulic infrastructure — now actively revisited through modern GIS, hydrological modelling and field evidence.
HARE Irrigation System
Conceptual engineering pathway
1995
River
Headworks
Main canal
Fields
Diversion weir
Under-sluice
Regulators
Canal drops
Conceptual web diagram only — not a reproduction of the original
engineering drawing.
Project overview
From River Hydrology to Irrigated Fields
The HARE Irrigation Project Design Report was completed in 1995 by Mesfin Hagos, Mitiku Bedru, Seid Shimelis and Tamir Mitiku as a Bachelor of Science in Engineering project at Arba Minch Water Technology Institute. At the time, the HARE irrigation scheme was already under construction by Chinese contractors. The student project therefore provided an exceptional opportunity to study, analyse and develop engineering calculations for a real irrigation scheme while its construction was taking place. The preserved report addresses the physical setting, irrigation-water quality, crop-water demand, hydrology, canal-system design, regulators, drops and diversion headworks.
Original study
1995
BSc Engineering design report
Study location
~10 km NW of Arba Minch
As described in the 1995 report
Water source
Hare River
River system draining toward Lake Abaya
Engineering concept
Diversion irrigation
Headworks + canals + control structures
Archival consistency note.
Professional records of the original team cite the thesis/design
project as “Design of HARE Irrigation Project (1500 ha)”,
while the abstract of the preserved 1995 report describes the
detailed scheme as irrigating a command area of about
1,000 ha.
The HARE Digital Archive preserves both source statements.
The difference will be reconciled only through continuing
document-by-document technical review rather than silently
altering the historical record.
Historical perspective
From Ancient Irrigation to the HARE Project
Irrigation engineering developed over thousands of years, from early gravity-fed canal systems in Mesopotamia and the Nile Valley to engineered diversion works, canal-control structures and today's GIS-based hydrological and hydraulic modelling.
HARE in 1995.
The HARE irrigation works were already under construction by
Chinese contractors when four Civil Engineering students at the
Arba Minch Water Technology Institute prepared the
HARE Irrigation Project Design Report.
Their work was an academic engineering study of a real irrigation
project then under construction; it did not represent construction
of the scheme by the student team. The 2026 reconstruction returns
to that study with modern data and modelling tools.
Physical setting
A Site Considered Favorable for Surface Irrigation
The 1995 report describes the irrigation area as gently sloping terrain associated with an alluvial plain. The land rises and falls locally and includes small erosion gullies, but the overall topography was judged favorable for surface irrigation.
Hare River is described as originating in the Chencha Mountains at elevations above 3,000 m above mean sea level and flowing through gorges toward Lake Abaya. The report gives an average stream gradient of about 3.5 percent.
Topography
Gently sloping alluvial plain, locally undulating,
considered favorable for surface irrigation.
Soils
Medium-textured alluvial materials including sandy loam,
loam and sandy clay; estimated infiltration rate of
approximately 10–30 mm/h.
Soil reaction
The report characterizes most soils as neutral to alkaline,
around pH 7–7.5, with no significant salinity problem
identified.
Rainfall record
For the climate data used in the original report, annual
precipitation is described as varying from approximately
625 to 1,054 mm, with two principal rainy seasons.
Original technical scope
Engineering Scope of the 1995 HARE Project Report
The report progresses from the physical and agricultural basis of irrigation to the hydraulic structures needed to control and deliver water. The sections below summarize the main design domains preserved in the original study.
02
Irrigation Water Quality
Assessment of sediment, dissolved salts, sodium, potentially toxic elements, bicarbonate, bacterial contamination, salinity and groundwater-management considerations.
03
Crop & Irrigation Demand
Crop-water requirements, effective rainfall, net and gross irrigation requirements, crop scheduling and diversion requirements using FAO-based procedures.
04
Hydrological Analysis
Analysis of Hare River flow records, annual peak flows, flood-frequency estimation and 1-in-5-year dry-period flows for design and water-availability assessment.
05
Canal System Design
Primary and secondary canals, field layout, tertiary drainage, canal capacity, permissible-velocity design and regime-theory comparison.
06
Regulators & Drops
Canal falls, distributary head regulators, cross regulators and related control structures for flow regulation, measurement, silt control and canal operation.
07
Diversion Headworks
Weir type and site selection, canal head regulator, under-sluice, divide wall, marginal bund and ancillary hydraulic works required to divert the Hare River.
08
Engineering Comparison
Comparison of calculated design results with information from the existing Hare irrigation works, including discharge, weir dimensions, canal layout and drop structures.
Hydrological foundation
Designing for Floods, Dry Flows and Irrigation Demand
Hydrology was central to the original study because the diversion and canal system had to be considered against both flood risk and water availability. The report analysed Hare River flow records, momentary annual peak flows and dry-period flows, and estimated irrigation demand using crop-water requirements and effective rainfall.
Peak-flow analysis
Annual momentary peak-flow records were used in the flood-frequency work supporting hydraulic-structure design.
1-in-5 dry period
Monthly dry-period flows were analysed as part of the assessment of dependable water availability for irrigation.
FAO-based demand
Crop evapotranspiration, effective rainfall and net/gross irrigation requirements formed the basis of crop and diversion-demand calculations.
HARE Revisited · 2026
Modern Hydrological Modelling Is Now Active
The modern reassessment has moved beyond planning. DEM-based watershed reconstruction, rainfall analysis, HEC-HMS design-flood modelling and SWAT continuous watershed modelling have now been completed to important intermediate stages and are being interpreted together with the original study and present field evidence.
Event-based rainfall-runoff modelling has been completed for the Hare Weir catchment. The adopted 50-year design-event simulation produced an outlet peak discharge of approximately 114.4 m³/s.
A continuous SWAT model has been developed for approximately 161.95 km² of watershed represented by 17 subbasins. Watershed delineation, HRUs, climate preparation and two successful simulations are complete.
SWAT Simulation 2 indicates an average upland sediment yield of approximately 58.4 Mg/ha and a strong modelled tendency toward channel deposition. Current field photographs independently show substantial gravel, sand and finer sediment accumulation at the diversion.
Important modelling distinction.
HEC-HMS and SWAT answer different engineering questions.
HEC-HMS represents event-scale design-flood response, whereas
the present SWAT model represents continuous daily watershed
behaviour, water balance, erosion and sediment processes.
Their discharge values should therefore not be interpreted as
equivalent hydrological statistics.
Water control
Canals, Regulators and Diversion Headworks
The original report compares two canal-design approaches: unlined sections based on regime theory and lined sections based on permissible-velocity criteria. The design process considers how silting and erosion affect canal capacity and full-supply depth.
Head regulators and cross regulators were treated as operating elements of the system rather than isolated structures. The report describes their roles in controlling off-taking discharges, measuring flow, reducing silt entry, maintaining upstream water levels during low flow, isolating canal reaches for repair and helping manage fluctuations in the network.
At the diversion, the original design scope includes the weir, canal head regulator, under-sluice, divide wall, marginal bund and associated works. The purpose of the headworks is to regulate river level and divert the required flow into the canal system, including during periods when natural river levels are low.
The modern reassessment adds a new emphasis on sediment management. Present field evidence shows substantial deposition around the diversion works, while SWAT indicates strong sediment generation in localized areas and substantial deposition within the modelled channel system.
Current design chain
- Hare River flow and flood assessment
- Weir and diversion-control concept
- Canal head regulator and under-sluice
- Scour and sediment-flushing requirements
- Sediment exclusion and desilting
- Main and secondary canal conveyance
- Cross regulators and distributary regulators
- Drop structures and turnouts
- Field delivery and drainage
Integrated canal design
From Command Area to Final Drawings
This workflow summarizes the complete engineering sequence used to move from command-area definition, water availability and crop demand through canal alignment, hydraulic section design, structures, final drawings and the bill of quantities.
HARE Revisited
Past Calculations, Present Understanding
The original report remains preserved as a historical engineering document. The modern reassessment is maintained as a separate technical layer that reproduces, tests and reinterprets the earlier work using modern geospatial data, rainfall products, digital terrain, hydrological models and present-day field evidence while keeping the 1995 calculations visible for comparison.
Original study · 1995
Engineering with the Data and Methods Available Then
- Field reconnaissance and available topographic information
- Historical climate and river-flow records
- FAO crop-water estimation procedures
- Manual / tabulated hydrological-frequency analysis
- Regime-theory and permissible-velocity canal design
- Conventional hydraulic and structural calculations
- Comparison with information observed from the HARE irrigation works then under construction
Modern reassessment · active 2026
Re-analysis with Modern Hydrology, GIS and Digital Terrain
- DEM-based catchment and terrain delineation
- GIS mapping of slope, drainage, land cover and command area
- Modern rainfall and hydroclimatic datasets
- Updated rainfall-frequency analysis
- HEC-HMS event-based design-flood modelling
- SWAT continuous watershed modelling
- Modern land-use and soil reconstruction
- Digital crop-water and irrigation-demand workflows
- Canal and drainage reconstruction
- Sediment-generation and channel-deposition assessment
- Field evidence from the present Hare diversion works
- Direct comparison of original and modern engineering decisions
DEM & Terrain
Modern GIS and digital terrain analysis have been used to reconstruct watershed boundaries, drainage, slopes, command areas, canal alignments and terrain conditions.
Catchment Hydrology
Rainfall reconstruction, flood-frequency analysis, HEC-HMS event modelling and SWAT continuous watershed simulation now extend the hydrological review beyond the original 1995 methods.
Land & Irrigation
Land use, soils, irrigable areas, crop-water demand, drainage and canal layouts are being reassessed using modern GIS, satellite information and engineering calculations.
Hydraulics & Sediment
Diversion headworks, canal structures, sediment generation, channel deposition, flushing, desilting and sediment-control requirements are now part of the active engineering reassessment.
Emerging engineering issue
Sediment Management from Catchment to Headworks
One of the strongest engineering findings emerging from HARE Revisited is that sediment should be considered throughout the watershed and diversion system rather than treated only as a maintenance problem at the weir.
Watershed source control
SWAT indicates strong spatial variability in sediment production, including localized bare-ground erosion hotspots. The modern assessment therefore supports targeted investigation of exposed ground, cultivated slopes and active gullies.
Potential catchment measures include bare-ground stabilization, contour cultivation, vegetative strips, terracing where slope and soil conditions justify it, gully rehabilitation and localized check structures.
Diversion-site control
Field observations show substantial gravel, sand and finer sediment accumulation around the existing Hare diversion works. Coarse sediment and bed load therefore need to be distinguished from finer suspended sediment.
Future headworks assessment should examine under-sluices or scour sluices, flushing routes, intake alignment, sediment exclusion, desilting facilities and routine operational sediment management.
Design requirement.
Final sediment-control design will require field information on
sediment grain-size distribution, suspended-sediment concentration,
bed material, river cross-sections, intake geometry, water levels
and available flushing discharge.
Why preserve HARE?
An Engineering Project That Continued Beyond Graduation
HARE is valuable not only because of what was calculated in 1995, but because the project became an early engineering foundation for four professionals whose later careers developed across complementary parts of the water sector.
Central HARE principle.
“Bringing the project back into print therefore connects
engineering education with professional experience, and past
calculations with present understanding.”
Original engineering team
Four Engineers, One Shared Technical Beginning
The Digital Archive gives each engineer an individual professional record while preserving the HARE project as a collective work.
MH
Eng. Mesfin Hagos Tewolde
Irrigation Engineer · Hydrologist · Civil Engineer
MB
Dr. Eng. Mitiku Bedru Gochefo
Hydraulic Engineer · Irrigation Specialist · Water Resources Leader
SS
Eng. Seid Shimelis
Irrigation & Water Resources Engineer · Dams · Headworks
TM
Eng. Tamir Mitiku Habeteyes
Hydraulic & Hydropower Engineer · Irrigation · WSS · Wastewater
Project history
1995 to HARE Revisited
1995
Original Design Report
While the HARE irrigation scheme was under construction by Chinese contractors, the four-member student team completed the HARE Irrigation Project Design Report as a Bachelor of Science in Engineering project at AWTI, using the real project as an engineering case study.
1995–2026
Professional Experience
The four engineers developed careers across irrigation, hydrology, dams, hydraulic engineering, WASH, wastewater, project leadership, government advisory work and digital water systems.
2026
Digital Archive
The original project is preserved online together with Team1995 professional histories, the project book, maps, source material and the modern technical record.
2026
HARE Revisited
Modern GIS, rainfall reconstruction, HEC-HMS and SWAT modelling are now being used to compare the original 1995 engineering decisions with present hydrological and water-resources practice.
Continue through the HARE Digital Archive
Explore the project book, Team1995, maps, GIS products, HEC-HMS design-flood analysis, SWAT watershed modelling and the continuing engineering reassessment.
