MONITORING AND EVALUATING

Monitoring perspectives of treated wastewater in irrigation

Growing volumes of both industrial and municipal wastewater are being discharged into surface waters, and the need for wastewater treatment and water quality monitoring are ever more emphasized to protect the environment and human health. Optimizing municipal systems and requirements to safeguard the environment and quality for reuse are aspects of concern for planners and decision-makers in water resources. A comprehensive monitoring programme is required to ensure that a proper treatment of wastewater is achieved and environmental degradation is prevented. Furthermore, monitoring and evaluation are essential requirements of any project that uses treated wastewater, and constitute a continual and integral part of operation and management.

The approaches to monitoring of irrigation systems are more extensive than for systems that discharge into streams as it incorporates reuse criteria. The objective of an irrigation site monitoring programme is to provide for early detection of problems in order to make adjustments to the operation of a treatment plant in avoiding ground or surface water pollution, as well as health-related issues. Aspects of monitoring are designed to protect public health and the environment and, ideally, these activities are planned at four points in the irrigation site monitoring system: 1) the treatment plant effluent; 2) storage; 3) irrigation system; and 4) any runoff areas such as soil, the vegetation and groundwater. Compliance with regulations and required control facilities and documentation such as sampling, analysis and comparability of data should all be incorporated in an integrated management plan.

Irrigation System and Ambient (Final Discharge) Monitoring

Integrated quality monitoring of treated effluent reuse for irrigation concerns the impact of treated wastewater constituents on the soil, groundwater, crops and eventual pathways to animals and humans consuming crops irrigated by treated wastewater. Quality control of the integrated system is aimed at ensuring that wastewater supplied meets the sanitary, agronomic and environmental quality requirements for the selected crops. The agricultural plan, including crop selection and rotation, and seeding patterns do have a role in defining monitoring and evaluation plans. Product monitoring at the farm or market is also important in verification in the effectiveness of health-based targets set by the WHO. Products should be tested for E. coli or thermo tolerant coliforms and other pathogens such as Ascaris ova or rotaviruses. Metals such as arsenic, cadmium, nickel, etc., and other potential chemicals should be in compliance with CODEX Alimentarius standards and limits set for health safety.

Furthermore, monitoring and evaluation also relate to environmental aspects of wastewater use in agriculture such as salinization of the surface soils, contamination of groundwater supply and surface drainage flows that discharge into the river. Parameters monitored include effluent flow and chemistry, shallow and deep groundwater level and chemistry, surface water chemistry, distribution of salts in the soil profile, soil heavy metal content and crop yield. Ideally, monitoring program should also include drainage and fertilizer requirements and the soil-plant system, as well as maintenance of technological database to determine environmental impacts of the effluent application.

The following are some general chemical quality parameters as related to irrigation, which might be regularly or periodically monitored by farmers or, for the farmers through official authorities (FAO 2003):

• Salt load or ECw = Electrical conductivity expressed in units of dS/m referenced at 25˚C. It is one of the most commonly measured parameters, particularly in arid and semi-arid regions, to estimate the total amount of soluble salts in water. Salinity is probably the most important single parameter, which determines cropping pattern and management of fields irrigated with wastewater.

• Cations and anions such as Ca, Mg, Na, CO3, HCO3, SO4, Cl. Some of these ions may be monitored at the beginning and then periodically.

• Some other ions such as Boron (B) must be monitored regularly in cases where detergents containing B are widely used. B in wastewater might be the main limiting factor for its reuse for irrigation.

• Sodium Adsorption Ratio is the most widely used index to measure physico-chemical changes in the soil:

SAR = NA/[(Ca+Mg)/2]1/2 where ionic concentrations are expressed in meq/l.

Heavy metals and trace elements (Al, As, Ba, Cd, Cr, Cu, Fe, Pb, Li, Mn, Hg, Ni, Se) are to be determined at least once before initial irrigation.

Effective Management at Relevant Levels

In the past, the responsibilities in general monitoring of wastewater quality have been in the hands of government authorities with little involvement from the farmers who are directly at the reuse site. The quality depends on the treatment itself, on maintenance and operation of the treatment system, and on the quality of operational staff at the treatment plant. However, limited training of farmers has been implemented with visual or simple tests, but this could prove to be very useful in assessing wastewater quality prior to irrigation use. Farmers could be provided training on aspects relating to colour of wastewater or extensive algae growth as indicators of chemicals and nutrients in the wastewater, and odour as indicator of insufficient treatment. Farmers’ rights to information and access related to water quality and type of treated reclaimed water for which they are provided are important in the entire monitoring and feedback plan.

FAO Activities

The Food and Agriculture Organization (FAO) provides technical assistance to countries in Integrated Water Resources Management (IWRM) and safe use of reclaimed water, in the prevention of environmental pollution for the protection of health and ecosystems, as well as in international data collection and monitoring.

FAO has developed a Wastewater Database (http://www.fao.org/landandwater/aglw/waterquality/dboverview.stm) from networks established containing information on wastewater production, treatment, reuse, as well as economic information provided by Member States. FAO provides direct country support through various mechanisms on wastewater treatment and reuse with the main objective of improving efficiency of water use for crop production, through proper treatment of sewage effluent for irrigation. FAO also engages in Farmer Field Schools to train farmers on the safe reuse of treated wastewater for irrigation and farmer monitoring of water quality and has written manuals on the safe reuse of treated wastewater in irrigation.

In summary, with increasing water scarcity and pollution problems, international trans-boundary basin issues and judicious water resources planning and management, inclusive of irrigation development, has become more and more important. Without proper monitoring, knowledge of the real magnitude of the issues cannot be achieved. Various international initiatives are aimed at an integrated framework for new approaches to water, food and the environment and to economic and social activity and development. This all requires positive will at all levels of the political and corporate spectrums, and the involvement of multi-stakeholders in order to meet the desired improvements towards a sustainable future.

For more information contact Sasha Koo-Oshima, Water Quality and Environment Officer.
[email protected]

Applying an evaluation methodology for social impact in a small-scale irrigation district in Colombia

Introduction

The Government of Colombia has developed about 600 small scale irrigation districts to benefit 24 000 small farming families in an area of about 40 000 hectares. The implementation of this infrastructure is part of a rural development strategy known as The National Programme for Small Irrigation (Programa Nacional de Pequeña Irrigación) which is supported by the World Bank and the Interamerican Bank of Development.

The lack of evaluation methodologies available involving the communities participating in the project does not allow to appreciate the benefits or the damage caused by the new infrastructures through its effects and impacts. In general, the evaluations consider only institutional, technical or economical aspects and do not refer to the users of the districts. An alternative methodology was proposed by Castro and Chaves (1994) to analyze a case study in Colombia: the irrigation district of Albesa in the Department of Cundinamarca.

Methodology

The methodology proposed is made up of the following elements:

1. The analytical reconstruction of the problem including, among others, the following elements: i) identification and characterization of the actors involved; ii) definition of the main problem that gave origin to the project; iii)determination of the descriptors of the problem and, iv) construction of the analytical and operational tree of the problem.
2. Evaluation of the Internal Consistency of the project, including: i) revision of the feasibility studies and design; ii) determination of the development, the general and the specific objectives; and iii) identification of the participating populations and their social coverage.
3. Evaluation of the Management and Efficiency of the project, established by means of: i) analysis of agreement between the supposed reasons of the diagnosis and the descriptors of the problem; and ii) analysis of agreement among the multiple factors and the specific project objectives.

The reconstruction of the problem that gave origin to the project indicated, among others, the following incident factors: low income of the farmers; uprooting and migration of the families from the countryside; very poor marketing; lack of irrigation water; and deficiencies in the productive agro-ecosystems.

Table 1. Project results by objectives and operations (in Colombian pesos)

* Efficacy = Final objective/Initial objective
** Efficiency = Initial timing/Final timing
1 USD = 2 350 Colombian pesos (2004)

Table 2. Some effects of the project activities

Table 3. Some examples of project impact

The Internal Consistency of the project was determined correlating the reasons of the diagnosis with the development and the specific objectives.

In the Evaluation of the Management and Efficiency, the descriptors of the problem and the reasons for the diagnosis presented a medium size incidence relationship. The supposed reasons of the diagnosis with the major level of agreement were: the iniatives of the leaders to execute the project, the existence of communitary organizations to support the project; the National Programme for Small Irrigation and Integrated Rural Development Project (Proyecto de Desarrollo Rural Integrado) supporting the project. Conversely, the lack of water resources, the low soil productivity and the low income are the critical factors mostly related to the operations of the project.

Evaluation of the Results

The information was gathered in 45 working days. The results are summarizad in the following tables according to the different elements considered in the evaluation exercise; namely, objectives, operations, effects and impact.

Conclusions and Recommendations

The general objective of the project was to evaluate in a participatory way the effects and impacts caused by the construction and work at the Albesa small scale irrigation district. The evaluation was made through the use of the methodology adapted and applied. To evaluate the project, a comparison is established between the situation “without” and “with” the project, hence identifying the effects recognized by indicators previously selected. Additional information was obtained in order to establish which impacts were related with the objectives of the participation of the institution in the National Programme of Land Adequacy.

The results of the project by specific objectives indicate that these were satisfied concerning the area covered, the number of beneficiary families and the engineering works. There was inefficiency on the use of the resources and in timing. The efficacy was high in the operational training objectives, in particular the workshops, but it failed in the training activities planned for organizational matters.

Concerning the operations, the more efficient activities were those related with the initial studies and the design that were satisfied in full. Those less efficient were the timing of the engineering works, including the installation of the outlets, the determination of the families to make the improvements and their financial participation to finalize the water distribution works at farm level.

CapDevWater Web site: http://www.fao.org/landandwater/cdwa

The most positive and evident effects caused by the project were the generation of new employment, the introduction of technological changes, the changes in the commercial relations and the organizational strenghthening. There were no evident negative effects, if at all.

As a recommendation, it is worth underlining that the participation of the users in all the project phases is fundamental for the farming communities in order to apprise themselves of the irrigation system and of the territory, demonstrating the collective work made to develop it. The institutional view of the land adequacy should incorporate anthropological considerations in order to have a more integrated approach to the irrigated agriculture and be able to define more coherent policies in line with the social reality of the project.

For more information contact Alvaro Bocanumenth P. in: [email protected]