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Agricultural Water Management 98 (2011) 705–714

Contents lists available at ScienceDirect

Agricultural Water Management

journa l homepage: www.e lsev ier .com/ locate /agwat

olumetric water control in a large-scale open canal irrigation system with manymallholders: The case of Chancay-Lambayeque in Peru

eroen Vos, Linden Vincent ∗

rrigation and Water Engineering Group, Centre for Water and Climate, Wageningen University, Droevendaalsesteeg 3a, 6708 PB Wageningen, The Netherlands

r t i c l e i n f o

rticle history:eceived 26 May 2010eceived in revised form5 November 2010ccepted 17 November 2010vailable online 16 December 2010

a b s t r a c t

Volumetric water control (VWC) is widely seen as a means to increase productivity through flexiblescheduling and user incentives to apply just enough water. However, the technical and social require-ments for VWC are poorly understood. Also, many experts assert that VWC in large-scale open canals withmany smallholders is not feasible. This article debates the practice of VWC, drawing on field studies inthe arid North Coast of Peru. Here the large-scale Chancay-Lambayeque irrigation system achieved high

eywords:arge-scale irrigationrrigation service feesolumetric delivery

allocation, distribution and financial performance with on demand delivery to some 22,000 smallhold-ings, under a VWC approach, with full cost recovery for operation and maintenance. This study showsthere are options to promote VWC if its different elements – volumetric allocation, distribution, meteringand pricing – are planned together.

© 2010 Elsevier B.V. All rights reserved.

ater user association

erformanceeru

. Introduction

Water is increasingly a scarce resource in many parts of theorld, with irrigation often a key user. More and more, irrigation

s targeted as a sector that should produce more with less water,here changes in operational management of large-scale irrigation

ystems can improve performance (Molden, 2007).A system of irrigation management that could potentially

upport good performance of large scale irrigation systems is vol-metric water control. We define volumetric water control (VWC)

n general as a system of water allocation, delivery, metering andharging where exact volumes are assigned on request to individ-al plot holders or groups of irrigators. There are different practicesossible within these dimensions of VWC, but it is important theyllow some freedom to the user in scheduling the timing and quan-ity of water turns. Restrictions on unlimited on-demand purchases

ay also be present in which case they are not based on “freearket” principles, mostly for reasons of social acceptability across

sers (see also Molle, 2009).This paper emphasises how the elements of allocation, delivery,

etering and charging need to be designed together in VWC tochieve good performance. In a VWC system the water users pay pernit of ordered (or received) water that they request. This systemequires precise water distribution and metering of the flows. It

∗ Corresponding author. Tel.: +31 317 484190; fax: +31 317 419000.E-mail address: Linden.Vincent@wur.nl (L. Vincent).

378-3774/$ – see front matter © 2010 Elsevier B.V. All rights reserved.oi:10.1016/j.agwat.2010.11.008

equally requires registration and charging for the water deliveredto each water user. The farmers, thus, are aware of water allocationand have, if unit prices are sufficiently high, an incentive to applyno more water than needed by the crop.

In this paper we discuss a VWC system where farmers applyfor water within certain overall volumetric restrictions based oncrop zoning and specific crop water allowances and water avail-ability in the river. It presents a brief review of arguments for andagainst VWC, then the findings of research on the practice of VWCin the large-scale Chancay-Lambayeque irrigation system (CLIS) inthe arid North Coast of Peru. The CLIS system was selected as one ofthe few applying VWC in a large scale system with open canals andmany smallholders. This system achieves good delivery and finan-cial performance despite a number of challenges. Field researchwas undertaken in CLIS from 1998 to 2000 (see Vos, 2002) with anupdate in March 2010 to study the continuation of the high perfor-mance in water allocation, delivery and service fee recovery foundin the earlier field study. The field research included flow mea-surements, questionnaires with water users and interviews withfarmers, operators, Water Users’ Association (WUA) board mem-bers, and government officials. The conclusions summarise the keymanagement dynamics enabling VWC to work in this system.

2. The concept of volumetric water control: difficulties andoptions

There are two main reasons for promoting VWC. The first reasonis improving field application efficiency, improving productivity

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06 J. Vos, L. Vincent / Agricultural W

f diverted water, and reducing risks of waterlogging and salin-ty (FAO, 1996; Merriam et al., 2007). The idea is that water users

ill request only the volumes of water that the crops require andot more. With increased field application efficiency the reduction

n water applied would not affect production.This outcome requires a charge per unit of water sufficiently

igh to induce the farmers to change their farming practices – forxample by no longer using water as a substitute for labour or othernputs (Levine, 1980).

The second reason to promote VWC is that a better water deliv-ry service (adequacy and timeliness) increases the legitimacy ofrrigation service fee payments. Thus, flexible delivery might alsonduce more effective accountability mechanisms and increase feeecovery rates (Malano and Van Hofwegen, 1999).

This practice of VWC is not without difficulties. Writers likeornish et al. (2004), Laycock (2007) and Molle (2009) point out thehallenges of measuring and monitoring water in large-scale sys-ems with open canal systems and many small users. Most authorsssume a device for metering has to be installed to charge users perelivered volume (Sampath, 1992; Burt, 2007). It is very difficultnd costly to measure and register all water flows to many small-olders, who may also steal water, informally exchange water turnsr take water in relatively small quantities. Metering at the level ofhe individual users in large scale irrigation systems can mostly beound in modern piped systems in richer countries, which use waterrom dams or pumped water. Indeed for example in Spain, Italy,

orocco, Australia and USA several such systems can be found.The challenge is to find a procedure to verify quantities delivered

hat is acceptable both to the farmers and to the operating agenciesithout being unduly expensive. Volumetric charging can also beone by methods of payment per hour using an approximate flowate (without need of an exact measurement of the flow rate). Ifrovider and user can agree on the approximate flow rate actuallyelivered, the payment can be made per day or hour of delivery. This

s done in Turkey (Murray-Rust and Svendsen, 2001) and in Perufor example in the Río Cachi and CLIS systems, see Vos, 2002).

Similarly, the distribution of exact volumes is likely to be chal-enging in large-scale systems with open canals and gated systemsnder operator control, because of vulnerability to breakdown,onstantly fluctuating flow targets, unsteady flow and tamper-ng, especially when the canal supply is irregular (Wade, 1990;ampath, 1992; Plusquellec et al., 1994; Horst, 1999). To be ableo distribute water in precise quantities, to precise locations, athe right time, requires a high degree of institutional and physi-al control over the water flows. Many experts, therefore, suggesthat modernisation1 of the irrigation infrastructure is necessary,mplying sophisticated water management and distribution infras-ructure, like pressurised buried pipe systems (Van Bentum andmout, 1994), automation of the operation of control structuresPlusquellec et al., 1994; Burt and Piao, 2004) and installing flow

easurement structures (Lee, 1999).For low-income countries, Horst (1999) and Mangano (1996)

xpress concerns that automation of control structures or trans-ormations to pressurised systems are too expensive, both innitial investments and in operation and maintenance. Volumet-

ic distribution would imply over-sizing of the infrastructure toccommodate peaks when many users demand simultaneously andould require well-trained staff to effect the on-request schedul-

ng. However, institutional capacities and skills of the operators

1 VWC is presented as a “modern solution”, however, the idea of VWC has a longistory. VWC was introduced – albeit without much success – in the large-scale

rrigation systems in for example the British Bombay Presidency in 1903 (Boldingt al., 1995), in Punjab in 1917 (Erry, 1936) and with more success in Peru in 1928Anonymous, 1929).

anagement 98 (2011) 705–714

should not be underestimated for gated control of open canal sys-tems. The possibilities for volumetric control in open canal systemsdepend on the institutional design and specific conditions.

Grimble (1999) underlines the economic rationality of VWC, inthat to make pricing an effective instrument for efficient waterutilisation then the amount the user pays should relate to actualdelivery (while possibly maintaining or increasing water consump-tion by the crop by means of better irrigation water applicationmethods). However, a frequently mentioned problem is that noappropriate procedures are in place to establish a proper priceto be paid per unit of water (Small and Carruthers, 1991; VanSteenbergen et al., 2007). The volumetric water payment shouldprovide sufficient economic incentive to conserve water (Tsur et al.,2004). In practice almost all large scale systems apply flat feesthat result in cost recovery below actual operation and mainte-nance costs (Molle and Berkoff, 2007). However, some irrigationsystems have established volumetric fees based on metered deliv-ery (mostly in USA, Australia, Morocco, Spain and Italy): see Cornishet al. (2004) for an overview.

In the case study below we show how volumetric allocation,scheduling, pricing and metering are made to work. We argue thatVWC can only be properly understood if the specific local condi-tions and institutional structures are taken into account, including:the operational supply and water demand of current cropping pref-erences, climate, the skills of the operators, the relative waterscarcity, the hydrology of the river basin, established water userights (Levine, 1980) and financial structure. It is crucial to considerthe effectiveness of the user participation and accountability mech-anisms installed between agency, canal operators, and differentgroups of users (Levine, 1980; Vos, 2005).

3. The Chancay-Lambayeque case in Peru

The CLIS (official name: Distrito de Riego Regulado Chancay-Lambayeque) is an ancient irrigation system, its main canal was firstconstructed some one thousand years ago. The scheme is situatedin the extreme arid coastal zone on the North Coast of Peru, withno effective rainfall in normal years. Only during “El Nino” yearsdoes rainfall occur. The water comes from rivers of unpredictableregime that run from the Andean mountains. The command area atpresent is some 100,000 ha. In 2009 a total of some 22,200 users hadwater rights: this ownership pattern evolved since the land reformsof 1969. At the time of research, three sugarcane enterprises hadlarge estates in the head of the system. The rest of the users weresmallholders with some 5 ha on average. They grow rice, cotton,maize, beans and other crops.

No groundwater is used in the system, as the small net returnsto staple crops like rice do not support pumping costs and becauseof the salinity of the groundwater. Deep percolation from canalsand fields contribute to water logging and return flows are hardlyused because of the proximity of the irrigation system to the ocean.

Fig. 1 presents a general map of the CLIS. The canals are mainlyunlined and the undershot gates are operated manually. The flowsare adjusted daily according to the farmers’ demand and availableriver supply. In 1992 the management of the CLIS was turned overfrom the Ministry of Agriculture to the WUA. The WUA introduced apayment per volume delivered to increase the fee recovery as sub-sidies on operation and maintenance were no longer received fromthe Ministry of Agriculture. The payment per volume also inducedan increase of the cropped area.

4. Public management and operation: 1969–1992

The Ministry of Agriculture took over the management of thescheme from the large landowners after the land reform of 1969.

J. Vos, L. Vincent / Agricultural Water Management 98 (2011) 705–714 707

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he local irrigation agency (Administración Técnica del Distrito deiego – ATDR), functioning directly under the Ministry of Agricul-ure, was responsible for the allocation, scheduling and distributionf irrigation water, maintenance and Irrigation Service Fee (ISF)ecovery. The government agency delivered the water to the headf the tertiary canal. As the system had to function in the facef very uncertain water supplies, a nested set of graduated rulesas developed to regulate allocation and delivery in relation toater availability. These came into effect at different times across

he cropping seasons depending on anticipated and actual watervailability.

The first echelon of rules for regulating allocation and schedul-ng related water delivery with type of water right. Since ancientimes, two types of water rights have existed: a permanent right“licencia”) and a right to excess water only (“permiso”). Many farm-rs have both a piece of licencia land as well as a piece of permisoand. The second level of regulation occurred through demarcationf cropping zones with a maximum water allowance per crop. Thisoning was related to the location within the system: sugarcane inhe head-end, paddy in the middle-reaches, and maize, cotton andeans in the tail-end areas. When the irrigation season was pre-icted to face relative low river and reservoir water availability, amaller zone for rice was allowed. Water users were allocated a cer-ain maximum volume of water per hectare (“módulo”) according tohe crop permitted to grow by the Ministry. The módulos are ratherigh compared to the crop water requirements: 20,000 m3 ha−1 forugar cane; 14,000 m3 ha−1 for rice; and 7100 m3 ha−1 for maize.here was not much monitoring of the actual crops grown, ratherhe water was distributed according to the allowed crop.

The “rangos” are the third echelon of regulatory adjustment,pplied in water scarce periods (when water demand is more thaniver supply during the growing season). Under the rangos system,ater demand was reduced by allocating water to only part of the

icencia plots of all water users. With increased holding size, the

ercentage of reduction in water allocation increased as well. Forxample, land holdings of less than 3 ha could still request up tohe full water allocation of 14,000 m3 ha−1 in the case of rice. Thoseith landholdings from 3 to 6 ha could purchase only up to 80% of

his allocation for each hectare. For landholding bands of 6–10 ha,

bayeque irrigation system.

10–20 ha and over 20 ha, this allowance was reduced respectivelyto 70%, 60%, and 50% of the módulo per hectare. Thus, the rangosfavour the smaller landholders, but also create problems of salin-ization, as scattered throughout the whole paddy area patches ofland will be lying fallow.

The fourth echelon for adjustment was the daily scheduling.Reductions in water allowances during scarcity period could befurther enforced by decreasing the frequency of the irrigation turns.

Thus, the daily scheduling of water was related to available riverand reservoir water and standardized crop water requirements ofthe planned crops. The scheduling was not on the demand of thewater users. The irrigation service fee (ISF) was set low and relatedto the area irrigated and crop allowed to be grown. The fee recov-ery was generally high, because state agencies provided inputs andbought the produce against guaranteed prices. The inputs and ISFwere deducted from the final payment to the farmer. However, thebudgets for operation and maintenance (O&M) were not directlyrelated to ISF recovery, and the fees recovered were insufficient tocover the O&M of the irrigation system. Maintenance of the canals,division structures and drains was neglected and bribery in thescheduling and distribution of irrigation turns was widely reported.

5. Management and operation by the water users’association: 1992–today

In 1992 the main system management was turned over fromthe Ministry of Agriculture to the water users’ associations (WUA)and subsidies from the Peruvian government for the operation andmaintenance of the system ended. The changes developed havecreated a sense of ownership of the irrigation system with theWUA. At main canal level, the elected board of the WUA – theJunta de Usuarios – and their company “COPEMA” took charge ofthe operation and maintenance of the reservoir, main canals andmain drains. To increase fee recovery the WUA introduced an ISF

per volume of water delivered and fee recovery through an advancepayment (registered in an automated administration). The sys-tem is divided in 13 sub-sectors (most sub-sectors have one mainsecondary canal). In each sub-sector a Comisión de Regantes tookcharge of the operation and maintenance of the secondary canals.

708 J. Vos, L. Vincent / Agricultural Water Management 98 (2011) 705–714

Table 1River discharge, total irrigated area, area cultivated with rice and fees recovered in the Chancay-Lambayeque irrigation system.

Irrigation season River discharge (million m3) Total irrigated area (ha) Area cultivated with rice (ha) Fees recovered (US$)

1970–1971 1578 74,943 23,506 nd1971–1972 1288 78,307 24,859 nd1972–1973 1070 76,434 21,683 nd1973–1974(*) 1111 80,626 26,578 nd1974–1975 1718 83,002 28,178 nd1975–1976 1179 85,532 34,829 nd1976–1977 933 73,695 30,823 nd1977–1978 614 67,700 21,468 nd1978–1979 811 73,444 19,970 nd1979–1980 375 39,271 1802 nd1980–1981 919 78,615 17,045 nd1981–1982 772 73,573 25,760 nd1982–1983 1659 80,249 36,512 nd1983–1984 1390 82,393 46,362 nd1984–1985 609 76,455 38,675 nd1985–1986 892 74,515 1738 nd1986–1987 985 89,034 42,322 nd1987–1988 894 69,247 27,051 nd1988–1989 1338 87,623 35,493 nd1989–1990 665 69,208 22,089 nd1990–1991 944 72,658 10,276 250,0001991–1992 628 64,246 15,513 500,0001992–1993 1254 80,035 17,893 1,300,0001993–1994 1382 94,127 37,928 2,100,0001994–1995 700 89,197 38,398 2,009,5141995–1996 1207 91,972 37,012 2,991,4341996–1997 584 79,829 31,758 1,758,1301997–1998 1561 82,968 37,482 1,350,2581998–1999 1283 95,276 45,414 2,374,5701999–2000 1304 94,319 44,378 3,135,1632000–2001 1438 94,241 47,739 3,418,6642001–2002 1182 94,755 50,274 3,779,8602002–2003 991 86,420 46,281 4,048,2592003–2004 553 54,586 10,571 2,105,3792004–2005 717 84,080 32,657 3,233,5522005–2006 nd 83,109 32,826 3,822,8642006–2007 1057 83,361 33,322 3,913,1412007–2008 971 88,827 35,366 5,169,2312008–2009 1604 95,316 41,957 4,998,183

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the implementation depends on the funds raised from the waterdelivery.

The discharge from the Chancay river is highly variable andunpredictable. The Tinajones reservoir has a capacity of some 317million m3 which is about one third of the average yearly diverted

Table 2Budget WUA 2010.

US$ year−1

ata from PEOT and Junta de Usuarios Chancay-Lambayeque.ee recovery corresponds to calendar year starting mid irrigation season.ees include flat fee (on average some US$ 10 ha−1, or about on average some 1 mil

he board of the Comisión de Regantes is elected every two yearsy the users served by the secondary canal. The board hires pro-essional staff and ditch riders to schedule and distribute water.t tertiary block level the users are organised in informal waterommittees (Comités de Regantes). The chosen leader of the ter-iary block is responsible for supervising the distribution of watermong users and organising maintenance of the distribution canalsnd secondary drains by local users.

Nevertheless, after the management turnover to the WUA theocal irrigation agency of the Ministry of Agriculture (ATDR) con-inued to issue water rights and plan the agricultural productioneason. The four echelons of graduated restrictions in case of inad-quate water supply have been maintained. The agency has limitedtaff and all planning is done together with representatives of theecondary canal WUAs. This joint planning includes defining cropones, crop water allowances (módulos), and whether cultivatorsill get water to irrigate their entire registered holding or only forpart of it in the coming irrigation season (using the rangos system).his joint planning is also done during the cropping season if furtherdjustments in scheduling are needed due to inadequate supply,ffectuated through further application of rangos and decreased

requency of irrigation turns. What has also changed is that farm-rs can now apply for the amount of water that they want for theirrops during periods of adequate river supply.

All operation and maintenance is financed with funds from theSF payments. COPEMA and the Comisiones de Regantes together

S$) and volumetric fee.

have a turnover of some 3.2 million US dollars per year (on averageduring the years 1994–2009, see Table 2). Only special rehabilita-tion works are financed with funds from the central governmentministries. Irrigation fees include a flat fee per hectare (someUS$ 10 year−1) and a volumetric fee. In years with relatively lowriver flows the income for the WUA from the volumetric fee isless, thus affecting the budget for O&M of the WUA. On averagethe income from the volumetric fees represents some 75% of thetotal income, although income from ISF varies widely over yearsbecause of fluctuations of river water availability (see Table 1).

In Table 2 the budget for O&M for 2010 is given. Every year thebudget for maintenance and especially “projects” is flexible and

General management 330,960Operation 730,028Maintenance 1,492,468Special projects 85,137Total 2,638,593

J. Vos, L. Vincent / Agricultural Water Management 98 (2011) 705–714 709

Table 3Módulo, crop water requirements and actual water allocations.

Módulo(m3 ha−1 year−1)

ETca

(m3 ha−1 year−1)Allocated in a year withrelative abundant river flow(1999–2000)b (m3 ha−1 year−1)

Allocated in a year withrelative low river discharge(2003–2004)b(m3 ha−1 year−1)

Sugarcane 20,000 15,000 13,000 9500Rice 14,000 7800 9500 7200

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ater. Annual river discharge has been between 375 and 2100 mil-ion m3, with an average of some 985 million m3 and a 75% chancef exceedance of some 690 million m3 year−1. There is a delicatealance between supply and demand.

The study showed that in a year with relative abundant riverow (for instance 1999–2000) the total water supply covers some0% of actual crop water demand of the allowed crops (resultingrom the agreed allocation). In a year with relative low river dis-harge (for instance 2003–2004) the total supply is only some 60%f the water demand of the allowed crops. Table 3 compares theverage water use per hectare by farmers in such years of differentupply conditions.

The net irrigation requirement for paddy, calculated with CROP-AT 8.0, was 7800 m3 ha−1, to which deep percolation losses have

o be added for leaching of salts. Table 3 thus demonstrates hown most years farmers use much less water than the maximum

ater allowance (módulo): for paddy between 7200 m3 ha−1 (in aear with low river discharges) and 9500 m3ha−1 (in a year withelative abundant river flow)2. Reasons for this lower applicationevel include the effect of any subsequent restriction on applica-ions allowed (if less water is available than predicted at the startf the irrigation season) and farmers’ own choice to purchase lessrrigation water.

Drains are well maintained by the WUA, and this is importants waterlogging and salinity are a major threat to the sustainabilityf the system. There is a constant pressure from the rice farmers toultivate their complete landholding with rice, and from the farm-rs of the adjacent “maize zone” to expand the rice growing area, asaterlogging and salinity limits growing of non-rice crops around

he rice growing zone. The WUA limits this expansion because riceequires more water which would not be available in most years.owever, as the volumes are controlled and not the crops quite

ome rice growing can be observed outside the rice zone: thosearmers grow a part of their plot with rice with a water allocationor maize3.

Each year in October the local irrigation agency, together withhe WUA, plan the coming irrigation season. Based on a long termeather forecast and the water available in the reservoir the next

eason is forecast as a wet, normal or dry year. De Bruijn (1999)howed that this weather forecast is highly speculative; neverthe-

ess it has been used in planning the last two decades. The totalrea allowed to be planted with paddy from 15 November to 15ecember is based on the forecast: the plan determines both theone that can be planted under certain crops, and the area of each

2 Actually application rates might be even lower because farmers may spread allo-ated water over their entire holding if they face a seasonal restriction on cultivablerea.3 The WUAs try to prevent rice growing outside the rice zone by only schedulingater to rice nurseries inside the rice zone during the period in which those nurseriesecessarily have to be established. No other crops get water during this period, thuso water is available to use illegally for rice nurseries. However, rice growers outsidehe rice zones bring seedlings from nurseries in the rice zone with pickup trucks toransplant on their fields when water is provided after the nursery period. No finesr other penalities are imposed.

3600 3000

holding that can be planted. A problem arises when an irrigationseason predicted to be “wet” turns out to be actually “dry” or “nor-mal” in January and February. Then each hectare already plantedwith rice will get less water than required. But there are also prob-lems if the season proves to be a “wet” year when they predicted itto be “normal” or “dry”: more water is available than can be usedto irrigate or stored in the reservoir and will flow into the ocean,while farmers had been obliged to leave (part of) their lands fal-low. In that case the local irrigation agency and WUA will be underheavy criticism from farmers and the local press. Also this situationmeans that the WUA loses potential income from ISF.

When demand is less than supply a state of abundance isdeclared. This state occurs about half the time during any irrigationseason. The state of water scarcity or abundance can be declaredand lifted from week to week during the irrigation season. Duringthe state of abundance the irrigation scheduling is on demand. Anyvolume of water can be ordered as long as it is paid for and usedon a plot within the allowed cropping zones. When water demandis more than supply the local irrigation agency together with theWUA apply the rangos system explained above.

Farmers request and pay for a water turn a day before the actualdelivery. They request a number of hours with a 160 l s−1 flow calleda “riego”. This relatively large flow at field level has been used formany centuries (Cerdán y Portero, 1793), and its rationale can beseen in the earlier large landholdings and flat area. Large flows inthe tertiary canals also reduce distribution losses. The sectorista(operator) in each Comisión de Regantes makes the schedule eachmorning in the office of the Comisión. If water is scarce the turnsare organized in a specific order and if necessary also fixed inter-vals are introduced to allow for more efficient distribution of scarcewater. In water abundant periods the WUA has an interest in sell-ing as much water as possible and no restrictions are applied onthe number of hours or the order of the turns.

Water is not metered at the farm gate. Instead, the farmers paya volumetric fee based on the hours of irrigation requested (witha flow of 160 l s−1). Special regulations are in place to compensatefor filling of canals and proven non-delivery.

In summary we can say that the scheduling is on demand dur-ing any time when supply is more than demand. This occurs moreor less half of the time. Table 4 shows the range of volumes ofwater purchased in one tertiary block in the tail-end subsectorof Muy Finca (in the relatively water abundant irrigation season1999–2000). More than 75% of the farmers purchased less than7000 m3 ha−1. Purchases depend on the crop grown, the salinityof the land and the preferences of the farmers. The data shows thatfarmers do consider the US$ 0.005 m−3 (or US$ 5.60 for 2 h irrigationturn of 1150 m3) a price that makes them think about the volumesto be purchased. Labour costs for requesting, monitoring of the ter-tiary canal and field application add some US$ 4.50 to the price ofa water turn.

Water is distributed in open canals, most are not lined. At bifur-cation points manually operated vertical undershot sliding gatesare used as cross regulators. Most secondary offtakes have Parshallflumes but along the secondary canals and tertiary canals no mea-surement structures are present. Water flow targets might vary

710 J. Vos, L. Vincent / Agricultural Water Management 98 (2011) 705–714

Table 4Differences in water purchase in one tertiary block due to farmers preferences. Ter-tiary block Sialupe, Comision de Regantes Muy Finca, 1999–2000 irrigation season.

Water use per hectare Frequency of farmers

m3 ha−1 No. %

0–1000 13 71000–2000 6 32000–3000 20 113000–4000 23 134000–5000 27 155000–6000 20 116000–7000 26 157000–8000 11 68000–9000 9 59000–10,000 6 310,000–11,000 5 311,000–12,000 1 112,000–13,000 2 113,000–14,000 2 114,000–15,000 1 115,000–16,000 0 0

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Table 5Irrigation Service Fee for 576 m3 (160 l s−1 for 1 h). Source:http://www.judrchl.org.pe and currency rates from http://www.oanda.com(accessed on 03 May 2010).

Year Soles Exchange range(soles US$−1)

US$ US$ m−3

1995 4 2.25 1.78 0.003

16,000–17,000 0 0>17,000 3 2Total 175 100

very 24 h in most points of the system according to the distribu-ion schedule established the day before to supply the registeredemands.

Experts would consider this system a “nightmare” system forelivering precise volumes to many smallholders on demand. Nev-rtheless, water delivery performance was found to be good (Vos,002, 2005). The Delivery Performance Ratio (DPR) is defined ashe delivered flow rate divided by the target flow rate, accordingo the accorded schedule. The Taymi main canal distributes waterirectly to some 13 secondary canals (see Fig. 1). The delivery toost secondary canals is measured with Parshall flumes. The DPR

f the water distribution to two sample secondary canals in theiddle and tail-end reaches of the system were 1.05 and 0.96 with

tandard deviations (sd) of 0.16 and 0.15. Only some gated crossegulators in the main canal provide for flow regulation. Canal oper-tors communicate by radio with the chief engineer to enable quickesponses to changes in actual flows and flow targets (see Vos, 2005or more details).

The secondary canals deliver water to many tertiary blocks. Fig. 2epresents the schematic layout of a typical secondary canal – inhis case the San Jose secondary canal located in the middle reachf the system (see Fig. 1). This has a capacity of 4.5 m3 s−1, a lengthf 10.4 km and serves 888 users and an irrigated area of 3794 ha.any gates and overflow structures regulate the water flow, but no

ow measurement structures are present. Nevertheless the waterelivery was fairly accurate. The DPR of water delivery towards theertiary blocks from two secondary canals in the middle and tail-nd of the system were 1.10 and 1.06 with sd of 0.21 and 0.44. Canalperators use informal markers, rules of thumb and the feedbacknformation they get from farmers on the delivery to the tertiarylocks and fields to adjust the distribution of the water along theecondary canal. Sometimes gate settings are “calibrated” with aurrent meter measurement.

Inside a tertiary block the farmers distribute the water. One toour simultaneous turns (with each 180 l s−1 at the intake of theertiary block) are delivered; see Fig. 3 for the layout of a typicalertiary block. The number of simultaneous turns might changevery 24 h according to the approved schedule. The distribution

nside the tertiary block is mostly regulated with sliding gates athe bifurcation points; with the help of informal markers. Thesenformal markers are also sometimes “calibrated” with a current

eter measurement. The average flows delivered to the farmers’elds inside two sample tertiary blocks in the middle and tail-end

2000 7 3.45 2.03 0.0042005 7 3.13 2.24 0.0042010 8 2.86 2.80 0.005

of the system were 148 and 153 l s−1 (as compared to the target flowof 160 l s−1). The difference with actual flows was mainly caused bywater stealing and more than average (or estimated) seepage lossesfrom the canal.

The good delivery performance is mainly attributed to three rea-sons. The first is the highly developed skills of the gate operators(whose level of education will normally not exceed primary school).They can fairly well regulate the flows to accommodate the dailychanges in target water flows.

A second reason is the high degree of accountability of the boardof the WUA towards the water users. Water users can effectivelypressure the board to deliver the agreed volumes. The operatorsare contracted directly by the boards of the WUA. Water users havetheir own informal markers to estimate flow size, and can requesta measurement of the tertiary flow with a propeller flow meterif they doubt the flow inside their block. If boards do not providea good delivery service they will not be re-elected in the electionsheld every two years. Board members appreciate their non-paid jobas board member as it offered the opportunity to start a politicalcareer, and in some cases illicit revenues can be made (from sellingwater and awarding construction works). The third reason is thesocial control among the water users inside the tertiary blocks. Thisprevents major water theft inside the block, although at the cost ofa high labour input guarding the water flow.

Rice yields are relatively high. Average paddy production issome 3.5 tonnes of polished rice per hectare, but some farmers pro-duce 7 tonnes of polished rice per hectare. Farm gate prices for ricevary within and between years, but on average are currently someUS$ 0.25 kg−1. High amounts of fertilizer and pesticides are used,and total production costs (including labour costs) are between650 and 1000 US$ ha−1 year−1 (including irrigation fees of betweenUS$ 25 and 50), resulting in net returns for rice between US$ 50 and500 year−1 ha−1.

The price of a “riego” (576 m3) has increased in nominal and realvalue since the beginning of the payment per hour (see Table 5).This is in contrast with many other reported cases where feeswere not corrected for inflation and went down in real value. InChancay-Lambayeque the charge of the “riego” expressed in US dol-lars increased from 1.78 dollars in 1995 to 2.80 dollars presently(keeping real value above an average yearly inflation rate of 2.50%).This is some US$ 0.005 m−3; a low price in international compar-ison (see Cornish et al., 2004). This was only the ISF paid to theJunta for the delivery from the main system. An extra flat fee (ofsome US$ 10 ha−1) and a small additional pro rata volumetric feeare paid to the Comisión de Regantes and sometimes the Comité deRegantes. The flat fee helps provide finance for management acrossa dry year. Apart from those fees also labour input was required forcanal maintenance in the tertiary block.

The fee is set in yearly General Assembly meetings attended byall water users in each Comisión de Regantes. In the October meeting

the board presents a tentative budget with corresponding activ-ities and the corresponding fee per hour of irrigation. If farmersagree with an increased budget the ISF has to be increased: if theywould agree with fewer activities the ISF could go down. How-ever, in practice the boards of all Comisiones, together with the local

J. Vos, L. Vincent / Agricultural Water Management 98 (2011) 705–714 711

ary ca

witp

Fig. 2. Second

ater agency agree upon an ISF beforehand, which is then defendedn the yearly meetings. Despite the “prearranged” price setting byhe boards, the discussions with users on activities, service levels,ersonnel, salaries and corresponding budgets and ISF, increases

nal San José.

the legitimacy of the ISF. In another General Assembly meeting inApril the water users exercise control on the board as they eval-uate the activities of the previous year and check actual budgetspending. While this control mechanism is not flawless, neverthe-

712 J. Vos, L. Vincent / Agricultural Water M

lap

fovrttwbUtftWd

tcwrc

Fb

D

Fig. 3. Tertiary block La Ladrillera–La Colorado (with 147 users and 676 ha).

ess some accountability of the board towards the water users isccomplished. Board members will not be re-elected if water userserceive management to be suboptimal.

The fee recovery rate is high: on average some 80% of the billedees are paid for. The smallholders pay in advance, and the sec-ndary canals receive a flow matched every day exactly to theolume paid for the day before. The percentage not recovered iselated to the three sugarcane estates that take water directly fromhe river. Some 25% extra water is allocated to the secondary canalo compensate for seepage losses. Actually, a small part of thisater is sold informally by the operators to water users that did not

uy an official water turn (at prices similar to the official price ofS$ 0.005 m−3). This informal water “market” does not affect nega-

ively the functioning of the system, although it deprives the WUArom a part of their official fee recovery (as the operators pockethe money). However, the unofficial water market also makes the

UA authorities, operators and water users all monitor the actualelivered flows very carefully (Vos, 2008).

Since the irrigation season 1992–1993 farmers pay for waterurns according to the volume requested. To assess the effect of

harging per volume the total cultivated areas from 1970 to 1992ere compared with the total cultivated area. Fig. 4 shows the

elation of the total cultivated areas with the total annual river dis-harges. The graph compares the time series 1970 to 1992 with the

Series 1: Irrigation seasons 1970-71 to 1992-93Series 2: Irrigation seasons 1993-94 to 2008-09

0

20,000

40,000

60,000

80,000

100,000

120,000

0 500 1,000 1,500 2,000

To

tal cu

ltiv

ate

d a

rea (

ha)

River discharge (millon m3)

Series1

Series2

Log. (Series1)

Log. (Series2)

ig. 4. Effect of charging per volume on the total cultivated area in Chancay Lam-ayeque.

ata obtained from the Junta de Usuarios Chancay-Lambayeque.

anagement 98 (2011) 705–714

flat fee crop-based fees with the areas irrigated in 1993–2009 withfees based on requested volumes. As can be seen the area increasesfor both series with more river supply. In the years 1993–2009the average total cultivated area is some ten percent higher thanthe averages for the period 1970–1993. Several management fac-tors may help account for this change, which cannot be related toany wider climate change or variability in this desert area or itscatchment4.

Overall the cropping zone patterns and water rights permittedhave not changed greatly, given the good control of irrigation andagricultural management organizations over cropping patterns5.There are annual fluctuations in areas of sugar cane grown by thelarger estates relating to prices which can affect water availabil-ity, but no major changes in planned areas. Water allowances forthe different crops are not released unless there is a cultivationplan that includes these crops – although sometimes a less waterdemanding crop is grown (and thus water availability is increasedif less water demanding crops like vegetables are grown). Equallyrice cultivated areas may fluctuate drastically (from under 2000 hain full drought years to over 50,000 ha in very wet years).

What has changed after 1992 is the withdrawal of the subsidiesand the consequent changes in roles of management organisa-tion that led to better planning and monitoring, and operation andmaintenance of the irrigation system. The increase in cropped areacan be related to both possibilities for farmers to cultivate theirfull holdings if water is available, spreading their allowed supply,or make operational savings in water use (at least so water doesnot flow directly into the drains). These diverse forces in turn allowfarmers with permiso rights to crop and irrigate their maize andbean systems more fully in years with surplus water. It is likelythat VWC has played a role in these changes. Firstly, it enabledthe finance of full operating cost recovery, enabling expendituresthat also improve performance. Secondly, the new administrationhas improved coordination of water requests. Thirdly, volumetriccharging has prevented overt waste of water. These all enabled abetter spread of water within the 100,000 ha area served by sys-tem infrastructure. More research could be done on these shifts incropping patterns and water use in space and time, in relation toexternal market forces and internal management practices.

6. Conclusion

Volumetric water control (VWC) is the volumetric allocation,scheduling, distribution, metering and pricing of water. VWC iswidely promoted for water conservation and financial accountabil-ity but also often seen as not feasible in large-scale open canalswith many smallholders. This article has shown that the Chancay-Lambayeque irrigation system achieved high performance with ondemand delivery to some 22,000 smallholders in a command areaof some 100,000 ha. The introduction of volumetric pricing in 1992has made possible the increase in the area cultivated within thepotential command area by some ten percent with the same riverdischarge. The WUA was able to fully recover costs for operation

and maintenance. The requirement to pay in advance of irriga-tion through an automated system also helped the liquidity of themanagement organization, except in years of relative drought, andassisted monitoring of water use and cropping activities. The volu-

4 There are no significant long-term changes in climate and rainfall over the irri-gated area or the river discharges from the mountains supplying the area. The ElNino effect (recurring on average once in 7 years) gives the heavier rains enablingthe same larger cultivated areas levels (and occasional destruction) in both timeseries.

5 Actually the WUA does not control the crop grown in the field. They control thevolume of water purchased for each field.

ater M

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J. Vos, L. Vincent / Agricultural W

etric pricing was not a free market: any sales of surplus water inood years were also clearly linked with registered users and land.maximum water allowance according to established crop type

nd irrigated area was determined and enforced in water scarceeriods. Thus, the on-demand scheduling and payment per hourf irrigation introduced some flexibility but area and crop restric-ions and graduated reductions in allowances were used to limitater demand in water scarce periods. These procedures providedsense of equity into the system, as water deliveries are reducedroportional with increased land holding. The price was correctedor inflation and was high enough to induce water conservation,nd finally set and agreed by farmers. The price was set for costecovery and not against any need for higher prices to force wateravings (which was mainly accomplished with pre-season restric-ions of land and crop types to be irrigated and subsequent moreestricted deliveries if necessary during the irrigation season). Therrigation fees only represented some 5% of the total productionosts (in the case of rice). Nevertheless, the price paid per hour ofrrigation (US$ 2.80) decreased instances of unnecessary and overtpilling of water (like allowing irrigation water to flow directlynto a drain), because net returns are relatively low. Also, full costecovery and better (on demand) scheduling contributed to bet-er performance allowing increased cultivated area. The system ofegistration enabled close adherence to water rights, and togetherith requirements of advance payment provided tools that limited

rregularities of water use. While some stealing did occur, this reg-stration system also made it public who should be irrigating at anyime, making unregistered and illegal users visible and the system

ore easily policed by users.The basic volumetric unit for a water turn was well under-

tood by users and operators. The operators proved very capableo operate the gates and had a range of incentives to operate theseell. Operators had employment contracts with WUAs. The water

llowance for crops were adequate in “wet” and “normal” years,upporting the arguments of Horst (1999) and Levine (1980) thatood water allowances make a gated system less open to tamperingnd more likely to work in a smallholder context.

Water delivery closely matched the planned on-demandcheduling. Several factors can explain these findings: the highegree of dependence of the water users on the canal water, theigh degree of accountability of the board of the WUA towards thesers, the relatively low degree of social stratification of the users,he financial autonomy of the WUA, and the good skills of the canalperators.

Three enabling conditions for VWC can be extracted from thease study that can be considered elsewhere. First, is the integratedpproach. To date, the discussion of VWC has too often focusednto only one of its elements, most strongly onto volumetric pric-ng or volumetric allocation and scheduling, or the technologyequired for volumetric distribution. Also too often, the justifica-ion may be on a particular desired outcome – water savings orost recovery, rather than an integrated management improvementnderstood and supported by farmers. This article emphasises howhere are four aspects of volumetric control that need to be devel-ped together – allocation and scheduling, distribution, meteringnd pricing. The WUA adjusted demand to unpredictable and highlyariable river supplies by graduated restrictions to the on-demandupply to farmers according to relative water scarcity. Seconds the crucial role of institutional design: in the case study theser participation, ownership, financial autonomy, accountability,ransparency, clarity and responsiveness were essential elements

o attain the high allocation, delivery and financial performance.hird is the smart use of flexible water distribution technology.o sophisticated technology was used, but some Parshall flumes,

adios and the automated administration of the daily water sched-le allowed for flexible and reliable volumetric water control.

anagement 98 (2011) 705–714 713

Equitable application of VWC is possible in large-scale smallholdercanal systems with this integrated approach.

Acknowledgements

The authors wish to express their thanks to Magdalena Guimacof IPROGA, Lima, Arturo Solórzano of the Proyecto Especial Olmos-Tinajones (PEOT) in Chiclayo and Alfredo Díaz of the Junta deUsuarios de Chancay-Lambayeque for collecting the data for the2000–2009 period.

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