Abstract: In this study, comparative indicators, which provide comparable analysis of irrigation performance among irrigation systems, were applied on K z l rmak Basin Irrigation and system performance was evaluated. As a result of the study, based on the 1996-2000 years output per unit command area, output per cropped irrigated area, output per unit irrigation supply, output per unit water consumed, total water supply ratio, gross return on investment and irrigation ratio were determined as 45-22443 and 247-43928 $ ha 1, 0.03-2.21 and 0.05-9.75 $/m3 and 0.74-6.20, 53-8708 and 8-98% respectively.
Introduction
In the first quarter of 21th century, several countries are coming face to face with important water problems due to increasing population, financial and environmental problems. Although water is a renewable resource, it is also a limited resource. The highest demand for water among the different sector occurs in agricultural sector and it plays an important role in the occurrence of environmental problems.
The irrigated land area per person increases to 48 ha in 1978, however this area decreased by 6% in recent years. Annual average increase in irrigated lands between the years 1980 and 1989 was 2.6 million ha. The decrease in irrigated land areas per person was especially seen in developing countries (Ünver and Tüzün, 2001). Most of the irrigation systems were not effectively operated because of the maintenance and operational problems. Every year, a certain amount of land area is becoming unproductive for plant growth due to soil salinity comes ponding to unproper irrigation practices and excessive water use. That is why, effective use of soil and water resources and performance evaluation of irrigation systems are highly important issues in irrigated agriculture.
For an effective watershed management, watershed water budget should be evaluated and water should be optimally allocated among the various sectors. Total water potential of the country from the 26 watershed is 186 billion m3 and only 95 billion m3 as this potential is used for different purposes. However, based on technical and economical criteria, total available surface and subsurface water potential is 110 billion m3. It is assumed that 95 m3 this potential can be applied from rivers inside the country, 3 m3 from the rivers among from out of country and 12 m3 from subsurface water. Annual water potential per watershed exhibits large fluctuations. Of 42 m3 water used in the year 2000, 75% was used for irrigation, 15% for drinking and utility and 10% for industry. Most of the water resources in the country is allocated to agricultural sector increasing water demand parallel to increasing population caused a decreases in the amount of water used in agricultural sector. This situation makes the water resources management an important issue and forces toward an effective use of water.
Governments aims the following issues by transferring the irrigation systems; sustainability of irrigation systems; improving the performances of irrigation systems; reducing operation, maintenance and management costs; effective use of resources. Like the other countries, irrigation schemes are transferred to user formed organizations. Transfer of irrigation schemes to time users are preferred by many countries in Asia, Africa, America and Fareast (Vermillion and Sagardoy 1999, Vermillion 2000). With support provided by World Bank in 19993, in Turkey, transfer of irrigation schemes to irrigation cooperations, municipalities and village authority was speed up (Çakmak et al., 1995). Significant improvements were achieved during the lost 8 years while 95.2% as irrigation schemes were operated by The State Hydraulic Works (DSI) in 1993, this rate was related to 9.6% in 2001.
Çakmak et al. (1995) has applied the performance indicators developed International Water Management Institute (IWMI) for performance comparison between irrigation systems on Irrigation Association in Konya region and evaluated the system performance between the years 1995 and 1999. In this study, standardized gross production value per unit command was determined as 195-5391 $ ha–1, per unit cropped irrigated area as 359-6197 $ ha–1, corresponding to the per unit irrigation supply as 0 02-1.29 $/m3, per unit water consumed 0.07-2.25 $/m3, water supply rate as 0.30-7.83 and irrigation rate as 36-104%.
Murray-Rust and Svendsen (2001) performed a study to evaluate the performance of 6 irrigation association as of SarIgol, Alaşehir, Adala, Turgutlu, Manisa and Menemen on Gediz Basin and determined the effectiveness of water as 20-40 $ ha–1. They also stated that after the transfer irrigation performance did not changed, cost were highly reduced and production of high market value crops played as supportive role.
Svendsen and Murray-Rust (2001) evaluated nationally the effectiveness of transfer programs in Turkey. They stated that water prices in irrigation association was 78$ ha–1 and 13% higher in DSI irrigations; the rate of water fee collection was 79% in irrigation association and 43% in DSI irrigation. They also indicated that a regular monitoring program was needed for transferred irrigation of DSI.
In this study, performance of 16 irrigation schemes within 5, 12, 19 and 23th regional irrigation district of DSI as of Agcasar, Fehimli, Gemerek, Germectepe, Gokceoren, Kalecik, Karacomak, Kızılırmak, Kovalı, Kumbaba, Sarımsaklı, Sarız, Suşehri, Taşhan, Uzunlu and Zamantı irrigation were determined and evaluated for the years 1996-2000.
Materials and Methods
With a connection to Black Sea, Kızılırmak basin is located on the east side of central Anatolia, Turkey, between 37°58’-41°44’, north parallels and 32°48’-38°22’ east longitudes. It has a surface area of 78180 km2 (Fig. 1).
Kızılırmak basin has a uniform climate with arid summer. Average annual precipitation range between as 300-800 mm and falls during winter and spring months. Basin average precipitation is 446.1 mm and temperature is 13.7°C.
Main river of the basin is Kızılırmak. Cereal farming is the dominating culture in the basin. Beside cereals, vegetables, potato, sugarbeet, sunflower, onion, garlic, beans, vineyards, fruits, chickpeas, lentils, common vetch, alfalafa, tobacco and corn are also grown in the basin.
There are 26 irrigation schemes, some of which has already transferred to irrigation association, constructed by DSI in Kızılırmak basin. 16 of these irrigation schemes, which have provided reliable data, were taken as the material of this study. These schemes are as follows: Agcasar, Fehimli, Gemerek, Germectepe, Gokceoren, Kalecik, Karacomak, Kızılırmak, Kovalı, Koprukoy, Kumbaba, SarmIsaklI, Sarız, Susehri, Tashan, Uzunlu and Zamantı (Table 1).
| Fig. 1: | The Kızılırmak basin |
| Fig. 2: | Stages followed in the study |
Irrigation area, irrigated land, diverted water, irrigation water requirement for the years 1996-2000 were taken from evaluation reports of irrigation facilities and cropping pattern, yield and unit prices were taken from reports of yield count results (Anonymous, 2001a,b).
| Table 1: | Irrigation schemes in the Kızılırmak basin (Anonymous 2002) |
| IA: Irrigation Association | |
| Table 2: | Data used on evaluation of irrigation system performance |
In this study, along with the other performance indicators, four comparative indicators developed by IWMI corresponding to unit area and water were used as performance indicators. These comparative indicators can be used to evaluate effect of interferences in irrigation schemes, to compare system performance based on time, and to compare performance of systems (Molden et al., 1998). If the limiting factor is water, than income per unit of water may be more important, or if the limiting factor is land, then the income per unit of land may be more important. Gross value of output per unit command area (GVCA), gross value of output per unit cropped irrigated area (GVIA), gross value of output per unit irrigation delivered (GVID), gross value of output per unit consumed water (GVCW), total water supply ratio (TWS), gross return on investment (GRI), irrigation ratio (IR) were calculated the following equations and excel spreadsheets (Fig. 2).
While evaluating performance of irrigation schemes in a region since the prices will be similar, gross or net production value based on local prices can be used as indicators. However, incase of different regions and countries, the local prices differ from each other. For a better comparison between the systems, the crop with the largest production in the region or country is taken as base crop. Then the other crops are standardized based on the local and world market prices of this crop and the corresponding standardized gross production value is used as indicator (Molden et al., 1998). Standardized gross production value is developed for performance comparisons among the irrigation systems different regions of the world in which local prices exhibit a change. In this study, standardized gross production value (SGVP) was used to compare on irrigation system performance with the other irrigation systems. Due to its wide range of production in irrigated areas as well as the utilization in world markets, wheat was taken as the base crop. SGVP was calculated by the following equation.
Where;
| SGVP | = | Standardized gross value of production, ($ ha–1) |
| Ai | = | The area cropped with i, ha |
| Yi | = | Yield of crop i, t ha–1 |
| Pi | = | Local price of crop i, ($/t) |
| Pb | = | Local price of base crop, ($/t) |
| Pdünya | = | The value of base crop traded at world prices, ($/t) dIr. |
Irrigation areas, cropped irrigated area, amount of water diverted to scheme, irrigation water requirement for the irrigation schemes considering in this study were given in Table 2.
Results and Discussion
Among the irrigation performance indicators, four comparative indicators (GVCA, GVIA, GVID and GVCW) are the measures corresponding to unit land area and unit irrigation water and the values of them calculated based on the local prices were given in Table 3 and Table 4. SGVCA ranges between 45-22443 $ ha–1 with Suşehri irrigation having the highest as of 22443 while Gökçeören irrigation having the smallest as of 45 $ ha–1 (Table 5 and Table 6). Different annual values obtained from each irrigation schemes were due to the change in cropping pattern and change of price of base crop in world market. SGVCA was determined as 6233 $ ha–1 in Bergama-Kestel Irrigation, 5003 $ ha–1 in Manisa-Alaşehir Irrigation 5003 $ ha–1, in Manisa-Turgutlu Irrigation 1469 $ ha–1, in AşağI Seyhan Irrigation 2167 $ ha–1, in Bursa Ulubat Irrigation 1070-1583 $ ha–1 and in Konya Irrigation Associations 195-5391 $ ha–1 (AvcI et al., 1998, Molden et al., 1998, Cakmak 1995). Performance of Salihli Irrigation Scheme between the years 1984-1995 using the IWMI performance indicators set. They determined that standardized gross production value per command area was 0.942-2238 $ ha–1; per irrigated area 1317-2585 $ ha–1, standardized gross production value corresponding to diverted water was 0.18-0.41$/m3 and standardized gross production value corresponding to unit water consumed 0.17-0.35 $/m3.
It carried out a performance evaluation study for Alto Rio Lerma Irrigation Association in Mexico and they determined that standardized gross production value per command area was 1840 $ ha–1; per irrigated area 2780 $ ha–1, standardized gross production value corresponding to diverted water was 0.16-0.00 $/m3 and standardized gross production value corresponding to unit water consumed 0.35-0.00 $/m3.
SGVIA ranges between 247-43928 $ ha–1. SGVIA was determined as 2732 $ ha–1 in Manisa-Turgutlu Irrigation, 2526 $ ha–1 in AşağI Seyhan Irrigation 2526 $ ha–1, in Bursa Ulubat Irrigation 2857-4415 $ ha–1 and in Konya Irrigation Associations 359-6197 $ ha–1 (Molden et al.,1998, Cakmak 1995).
SGVID ranges between 0.03-2.21 $/m3 and SGVCW ranges between 0.05-9.75 $/m3 with the highest value in Suşehri Irrigation and the lowest value in Gokceoren Irrigation.
| Table 3: | Gross production values regarding local price in irrigation associations |
| Table 4: | Gross production values regarding local price in DSI schemes |
| Fig. 3: | Water supply ratio in irrigation associations and DSI schemes |
| Fig. 4: | Gross return on investment irrigation associations and DSI schemes |
The difference between gross production value corresponding to unit irrigation land area and corresponding to diverted water and irrigation water requirement was due to change in diverted water to the scheme and change in crop pattern. SGVID in Bursa Ulubat Irrigation between the years 1992-1998 ranged between 0.31-.50 $/m3, in Konya Irrigation Associations between the years 1995-1999 it was ranging between 0.02-1.29 $/m3 (Cakmak 1995). Standardized gross production values obtained based on cropping pattern was exhibit a change. Based on studies carried out by IWMI on 18 irrigation system in 11 countries in the world since 1992, it was determined that the income obtained was found to be higher in irrigation schemes with higher rates of fruit, vegetable and industrial crops (Molden et al., 1998).
Water supply rates calculated based on total irrigation water requirement in the study area, range between 0.74-6.20. Based on the total irrigation water requirement, a water supply ratio of 1 indicates that diverted water was enough for the need, a value less than 1 indicates that diverted water was less than need, and a value more than
1 indicates that diverted water was higher than need. As it can be seen from Fig. 3, water supply rates in irrigation schemes varies with the years and highest water supply rates were obtained in Taşhan Irrigation in 1997 with a value of 6.20 and the lowest rates were obtained in Kumbaba Irrigation in 1996 with a value of 0.74. All of the irrigation schemes in the basin had diverted water more than the need. Beyribey et al. (1997a) carried out a study on 119 irrigation schemes in 21 region determined the water supply rates based the total irrigation water requirement that for June it was 0.29-1.67, for July it was 0.44-1.49 and for August it was 0.40-1.71.
| Fig. 5: | Irrigation ratio in irrigation associations and DSI schemes |
They found that water diverted to 38% of irrigation schemes operated by DSI in June, to 43% of irrigation schemes in July and to 62% of irrigation schemes operated by DSI in August were higher than the need. Cakmak (1995) determined the water supply rate in Konya Irrigation Associations between the years 1995-1999 as 0.70-7.83. Value as 0.91-7.15 for the irrigation schemes transferred to irrigation associations for the year 1998.
The gross return on investment used to analyze profitability of different irrigation systems ranges between 53 and 8708% (Fig. 4). The gross return rates calculated based on 1997 date by using the standardized gross production value and irrigation system cost values was found to be 130% in Bergama-Kestel Irrigation, and 88% in AsagI Seyhan and 125% in Bursa-Ulubat Irrigation (AvcI et al., 1998, Molden et al, 1998,). It can be said that the irrigation systems in the research area were highly profitable.
The highest rate of irrigation was obtained in Sarımsaklı Irrigation in 1997 with a value of 98% and the lowest rate of irrigation was obtained in Taşhan Irrigation in 1998 with a value of 8% (Fig. 4). Based on a study for 21 irrigation schemes in 21 irrigation region Beyribey et al. (1997b) determined the irrigation rates as 24-105% for the years 1984-1993. Beyribey (1997) determined irrigation rates for 199 irrigation schemes in 21 region for the years 1984-1993 and found that it was less than 30% in 74 schemes, between 30-60% in 72 schemes, and higher than 60% in 53 schemes, provided that the lowest irrigation rate was considered.
| Table 5: | Standardized gross production values in irrigation associations |
| Table 6: | Standardized gross production values in DSİ irrigation schemes |
It determined the irrigation rates for irrigation associations for the year 1998 as ranging between 4-100%.
It can be seen that although the water used was than the need, it wasn’t used effectively, in irrigation schemes of Kızılırmak Basin and the production values corresponding to unit land and unit water were low. Utilization of comparison indicators in performance evaluation has provided on opportunity to compare different irrigation systems. GVCA, GVIA, GVID and GVCW values obtained for sixteen schemes in this study are in good agreement with the results obtained by Molden et al. (1998) in 18 irrigation systems in 11 countries.
In this study, the irrigation association was found to have higher gross return on investment rates. Higher rates indicate higher rates of profitability. This situation outlines the after transfer successful management practices in Kızılırmak Basin irrigation schemes.
Water supply rate for both transferred and DSI operated irrigation was found both higher than 1. The reasons to diverted water more than the need were unproper application of a planned water delivery, water losses in scheme, unconscious irrigation applications, and collection of water fees being based on the land area. For a more effective water utilization in the country, irrigation water pricing approach should be reconstructed at basin level. Since the infrastructure to measure utilized water in a field base, is not sufficient, water fees are calculated based on irrigated land area and the crop types and in a few irrigation association "duration of irrigation-hour" (TL/hour) was used for water fees. The pricing based in volumetric usage should be initiated and application has to be speed up. Effective water utilization policies should be developed and irrigation schemes should be evaluated in groups based on basin.