Development, Testing, Training and Deployment of Irrigation Water Distribution Decision Support Tool -Case Study of Mwea and Bura Irrigation Schemes

Abdulahi M. and Owilla B.P.O.

To boost food production and stimulate socio-economic development, the govt through NIB is expanding irrigation in Kenya

However, the intensified sectoral and inter-sectoral water competition has reduced the amount of water available for irrigation

Sustainable irrigation expansion requires improving water-use efficiency and productivity

Inequitable distribution of water in the existing Schemes to attributed to to either lack of a distribution plan or difficulties in implementing one where available

Need to develop more effective management tools

BACKGROUND

IWP or IWUE = f{InF, MetF, WrcF, DsF}:o InF =irrigation typology (infrastructural factors) o MetF =irrigation water requirement (water

availability factors)o WrcF =water resource factorso DsF =distribution factors Model development Model testing Training of users and deployment of tool

METHODOLOGY

The typology module will include the irrigation canals network and area served/under each canal, water measuring and control structures, these information will be fixed and secured from accidental change. Also in this module is the seasonal cropping programme which states when each block or unit will start the lands preparation, seeding and transplanting.

METHODOLOGY:Irrigation Typology Module

The water resources module will contain: historical and near real time data on the river discharge at the points of abstraction or upstream of this point if no measuring structure/ measurement point is available near the abstraction site.

The module is expected to provide the available resource as well as

provide a forecast in to the near future (up to seven days) assuming a scenario where no rainfall occurs in the catchment upstream of the measurement site. From the historical river discharge database the module should be able to search the year that most likely resembles the current in terms of water resources availability

The module will have an input limit on abstraction which is either the permitted amount (at that period, if the permit is variable) or in the case of pumping scheme the pump capacity. It will use whichever is lower since for the case of gravity system you can only take the permitted amount even if the river has more discharge, in the case of pumping even if the permit is higher than the pump capacity what the scheme can get is dictated by the pump capacity. This module will also have an input on the number of working pumps and the working hours and other related details,

METHODOLOGY:Irrigation Water Requirement

This will be the output of module two to come up with a distribution plan (or flow rates) at various measuring points to ensure the water demand under each of the points is met. Although the ideal plan will be ready the module will refer to the available water resources by linking to module three. From here two scenarios are possible one in which the available water resources equals or exceed the total gross water requirement in which the ideal plan will be implemented which may be continuous flow in case of gravity flow. In the second scenario the available resources is less than the total gross scheme requirement in which case rotational irrigation supply will done. The level and cycle days for the rotational supply will be done by this module. This may be altered by the decision makers (managers) if need arises. The second scenario is normal in pumping schemes. The module will also have a feedback section where the staff can report the progress of the water distribution in the previous day.

METHODOLGY:Irrigation Water Distribution Module

This module will have embedded in it a reporting template for daily, monthly or annual/seasonal reporting of the irrigation water management for the scheme. The reporting module will be linked to the above modules and will be able to produce a variety of figures and tables to be embedded in the relevant template at the click of a button. The output data may include water conveyed to each unit/block, etc.

METHODOLOGY:Reporting Module

The work plan may be broadly divided in to four main activities: data collection and preparation, module development, testing, training and deployment.

It is estimated the it will take one year to undertake this research and development.

The data required for work is mainly the hydro-meteorological data, scheme maps and units/blocks areas, pumps capacities and operation details, water resources abstraction permit details.

WORK PLAN

THANK YOU

END