Metric matters : the performance and organisation of volumetric water control in large-scale irrigation in the North Coast of Peru

This thesis describes the organisation and performance of two large-scale irrigation systems in the North Coast of Peru. Good water management is important in this area because water is scarce and irrigated agriculture provides a livelihood to many small and middle-sized farmers. Water in the coast of Peru is considered to be badly managed, however this study shows that performance is more optimal than critics assume. Apart from the relevance in the local water management discussion, the study also addresses two internationally much debated topics in irrigation water management: irrigation management transfer (from government to water users' associations) and modernisation of infrastructure.Large-scale irrigation is often associated with low water use efficiencies, low control over the deliveries and low fee-recovery. Volumetric water control is one of the solutions proposed to solve these problems. The idea behind volumetric water control is to allocate and schedule precise volumes of water to meet crop water requirements, if possible on request of the water users. The user is charged per volume of water used to prevent over-use, and to raise sufficient funds to operate and maintain the irrigation system. Many authors stress the difficulties of volumetric water control. For example: on-request scheduling is too costly in large systems with many smallholders. High-tech automatic water control systems are too expensive and difficult to operate and maintain. Setting of the Irrigation Service Fee (ISF) might be too low to provide an incentive for water saving, or might be too high for poor farmers to pay.The study aims to achieve a better understanding of the practices in organisation and performance of volumetric water control in two large-scale irrigation systems in the North Coast. The coastal zone of Peru is extremely arid. Precipitation is near zero, except once in about 15 years when the El Niño phenomenon brings heavy rains and floods. The irrigation systems depend on the highly irregular rivers, which flow from the Andean Mountains. Main crops in the coastal areas are: sugarcane, rice and maize. Two systems were selected for a comparative study: Chancay-Lambayeque (100,000 ha) and Jequetepeque (40,000 ha). In the Chancay-Lambayeque system the users pay US$2 per 576 m 3scheduled to be delivered at field level. In the Jequetepeque system the farmers pay a fixed fee according to the crop allowed to grow. For example they pay US$ 60 per hectare of rice.The analytical framework highlights two main points: First, the irrigation infrastructure has certain properties, because different stakeholders designed and constructed parts of it in the past. These properties set certain requirements for use. For example the manually operated, undershot gates need skilled and experienced personnel to operate them well. The properties of the infrastructure also affect the water distribution in particular ways. For example a system with undershot offtakes and no check structures in the ongoing canal transports all fluctuations in the inflow to the tail-end of the canals. This affects the farmers in these areas. Second, the organisations can be regarded as 'semi-autonomous fields' where rules and regulations are transformed and local regulations are applied. Social power relations, technical properties, environmental conditions and the interests of actors influence the rules that are used, how and when. The different organisations that manage the irrigation system form a complex entity. At different levels in the system; water users' organisations, private companies and government agencies play a role in water management. This complex entity can be studied by looking at the domains of authority the organisations have, the rules they use, and the structure of decision-making and accountability between the organisations. Conflicts can reveal the rules used and the power plays involved. During one and a half year field research many key informants and water users were interviewed and a water flow measurement programme was executed.Chapter 2 describes the setting of the two irrigation systems: the natural resources, the long history of irrigation in the area and the present production systems. As the coast is arid and plain, waterlogging and salinity are dangers of irrigation. Irrigation began already 3000 years ago. The present main canal of the Chancay-Lambayeque system was built around AD 1000 and the irrigated area then was larger than today. After the conquest the Spaniards largely continued the management of the Incas. Only when the new settlers claimed increasingly more land for their haciendas, conflicts about water grew. State interventions in the management of the systems started early 20 thcentury. At that time the idea of volumetric water control was proposed. However, it was not until the Agrarian Reform of 1969, when the management became completely in the hands of the State, that volumetric allocation and delivery was introduced. And only with the Irrigation Management Transfer (IMT) to the Comisiones de Regantes and Juntas de Usuarios in 1992 volumetric charging was enforced. Today sugarcane and rice are cultivated in high input - high output production systems. Main problem for the small and middle-sized landowners is to obtain credit. The local rice purchasers ( molinos ) provide credit, which leads often to ever greater indebtedness of the smallholders. Execpt for the three sugarcane co-operatives the average landholding is 5 ha.Chapter 3 introduces the complex structure of the entities that manage the irrigation systems. Since the Irrigation Management Transfer in 1992 the Comisiones de Regantes (CRs) at the level of the secondary canals operate and maintain the secondary canals. The board of the Comisiones is elected by all water users. For the operation the board hires staff. At the level of the tertiary canals the Comités de Canal maintain (and sometimes operate) the tertiary canals. In 1994 (for Chancay-Lambayeque) and 1998 (for Jequetepeque) the Juntas de Usuarios formed private companies to take over the operation and maintenance of the main canal and reservoirs. The local irrigation offices of the Ministry of Agriculture (ATDR) retained the authority to allocate water (up to the individual plot level) and supervise the management by the water users' organisation. Besides the ATDR also the Autonomous Watershed Authorities (AACH) and the Special Project Bureaus are government organisations that have certain domains of authority in water management.The main difference in water use between the systems is that the water users in Jequetepeque apply on average twice as much water per hectare of the same crop compared to the users in Chancay-Lambayeque. This is not caused by the volumetric payment in Chancay, but by the difference in water availability per hectare. After the Land Reform the Chancay system was expanded to win political support with the new water users, whereas in Jequetepeque the luxurious water right position acquired by the haciendas was not changed.Chapter 4 describes the practices of volumetric water allocation and scheduling. The National Water Law of 1969 establishes that all water is property of the State and that the ATDR is the organisation that gives concessions for use to individual water users. The ATDR also establishes how much water each user can request maximum depending on the defined cropping zones. However, for the scheduling of water turns according to the cropping plan the ATDR depends on the Comisiones de Regantes . The Comisiones , however, generally comply with the cropping plan to avoid claims of water users for water they are entitled to. Apart from the permanent water rights ( licencia ) there are also water titles for excess water ( permiso ). This institution was already known in the pre-Inca times. It is an adaptation to the ever fluctuating river supplies. In Chancay-Lambayeque water is scheduled in ' riegos' . One riego is one hour of water delivery with 160 l/s at field level. The water users pay in advance and get the hours the next day. In Jequetepeque the turns are only scheduled at the beginning of the rice-growing season. During the remainder of the rice-growing season the water flows continuously from field to field.In water scarce periods, when supply is less than expected, the Junta de Usuarios together with the ATDR adjust the water allocations. In Chancay-Lambayeque all water users then get scheduled a fixed number of hours each 15 days. The number of riegos per hectare is proportionally less the bigger the landholding of the farmer. This results in plots only party planted with rice, but more often in plots completely planted, but deficiently irrigated. In Jequetepeque water scarcity comes less unexpected, because the reservoir has sufficient capacity for an irrigation season. Here certain campos (small clusters of fields) are excluded from rice growing when the reservoir is low.In Chapter 5 an assessment is made of the volumetric water delivery. First a framework for understanding delivery performance is given. In this framework three main factors are central: the physical infrastructure, the operators, and the water users. However, in the first place the Relative Water Supply (RWS) should be looked at. The RWS is the ratio of the delivered water and the crop water requirements. If the RWS at field level is higher than 1.5 water can be used as a substitute for control. An intensive water flow measurement programme was executed to assess the performance of the water delivery service. Water flows were measured at all levels of the canal system: from offtakes from the main canal to deliveries at field level. The Chancay-Lambayeque system with its manually operated undershot gates, few measurement structures, open and unlined canals, its irregular river supply, and complicated on-request scheduling for 22,000 water users is a 'nightmare' system. Nevertheless, the Delivery Performance Ratio (DPR) was remarkably close to 1.0 at different levels of the system, indicating that the actually delivered flows were as programmed. This together with a RWS of between 0.6 and 0.8 at field level leads to a high water productivity. The remarkably good water delivery performance was explained by the skills of the operators and the accountability of the boards of the Comisiones towards the water users. This accountability was a result of the board members wanting to win the next elections to remain in the position to make money from illegal water selling. Also radio and newspapers were used to exert pressure on the boards to perform well. In Jequetepeque the DPR was almost always above 1.0 indicating that there was more water distributed than programmed. This was explained by the fact the in Jequetepeque the RWS was about 2.Chapter 6 focuses on the financial conduct of the two irrigation systems. The charge for the water delivery service is set by the General Assemblies of the water users. They prioritise the expenditures of the Comisiones and therewith set the fee. The fees are recovered by the Junta de Usuarios (or its private company) and then distributed over the different organisations that manage the systems. The fee recovery was high. In Chancay-Lambayeque from 1993 to 1998 more than ninety percent of the distributed water was paid for (per volume). Users paid per riego , thus recovery was spread throughout the irrigation season. The advance payment could be enforced quite well because o social and technical control over the water. Only the sugarcane co-operatives in the head-end of the system took water without paying. A drawback of volumetric charging is that less river supply means less income for the organisations. Also in Jequetepeque the fee recovery was high. Here the farmers did not pay per volume and the recovery was harder to enforce because of abundant water availability. Therefore, the Junta collected the fees at the beginning of the irrigation season when the system was still dry but the rice farmers need to start their nurseries. By strict control over the water to only those users who had paid the fees of last year the Junta recovered the fees. The farmers could not wait with their nurseries until water would be available abundantly because a later start would mean a yield reduction due to low temperatures at the end of the season. This construction of technical, environmental and institutional elements that enforces the payment was called an 'obligatory point of passage'.Between 1.5 to 3.0 million dollars were collected each year in each system. This was more or less sufficient for operation and maintenance and paying taxes. The distribution of theChapter 7 evaluates the functioning and effects of volumetric water allocation, scheduling, delivery and charging. It is concluded that water control in Chancay-Lambayeque is volumetric. In Jequetepeque water allocation and distribution is only volumetric to a certain extent, and charging is not related to the volume actually applied to the field. In both systems there are two important factors shaping water management. First, the history of the institutions and physical infrastructure. Despite the many abrupt changes in the institutional setting the continuities in the long history contributed to the legitimacy of the rules and the functionality of the infrastructure. Second, the contemporary institutions bring about a power balance among the various organisations involved in irrigation management. The governance of the organisation follows surprisingly strictly the National Water Law. Only some minor rules are not complied with. Rule-compliance is partly enforced by social control among 'equal' parties: e.g. farmers in the tertiary block guard their water against theft, and engineers of the Comisiones ensure they get allocated water for their Subsector according to the rules. Rules are also enforced by the governmental organisations ATDR and AACH. They judge about certain types of conflicts (on rule violation) inside the users' organisations. Punishment of rule violation is also used in political ways: a fine by the ATDR implies exclusion of the involved water user from the next election of the board of the Comisión .The effect of volumetric water control on productivity of water is small. It is much more the water availability per hectare that determines the productivity of water. The water in Chancay-Lambayeque is 'stretched' over a much bigger area compared with Jequeteque making water more productive per volume of water applied. The volumetric charging affected livelihoods of poor farmers because it was difficult for them to find the money to pay the water turns when the crops required water. However, as the production system is high input - high output, the farmers invest much money anyway and the water fee is only 5 to 10 percent of the total input costs. The payment per volume made the board and staff of the Comisiones somewhat more accountable in water delivery to the water users.It is concluded in Chapter 8 that the power balance between the water users, different water users' organisations, private company and different public agencies shaped a well functioning entity. The general governance regulations were complied with, but locally rules on allocation, scheduling, maintenance and fee setting were refined and negotiated. It was also concluded that the analytical framework and research methods used in the comparative study were useful in revealing the complex nature of the irrigation management

Observation of quantum entanglement with top quarks at the ATLAS detector

Entanglement is a key feature of quantum mechanics with applications in fields such as metrology, cryptography, quantum information and quantum computation. It has been observed in a wide variety of systems and length scales, ranging from the microscopic to the macroscopic. However, entanglement remains largely unexplored at the highest accessible energy scales. Here we report the highest-energy observation of entanglement, in top–antitop quark events produced at the Large Hadron Collider, using a proton–proton collision dataset with a centre-of-mass energy of √s = 13 TeV and an integrated luminosity of 140 inverse femtobarns (fb)−1 recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable D, inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the top–antitop quark production threshold, at which the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from the limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be D = −0.537 ± 0.002 (stat.) ± 0.019 (syst.) for 340 GeV < mtt < 380 GeV. The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement so far

Study of Z → llγ decays at √s = 8 TeV with the ATLAS detector

This paper presents a study of Z → llγ decays with the ATLAS detector at the Large Hadron Collider. The analysis uses a proton–proton data sample corresponding to an integrated luminosity of 20.2 fb−1 collected at a centre-ofmass energy √s = 8 TeV. Integrated fiducial cross-sections together with normalised differential fiducial cross-sections, sensitive to the kinematics of final-state QED radiation, are obtained. The results are found to be in agreement with stateof-the-art predictions for final-state QED radiation. First measurements of Z → llγ γ decays are also reported

Search for leptoquark pair production decaying into te−te¯ + or tμ−t¯μ+ in multi-lepton final states in pp collisions at √s = 13 TeV with the ATLAS detector

A search for leptoquark pair production decaying into te−te¯ + or tμ−t¯μ+ in final states with multiple leptons is presented. The search is based on a dataset of pp collisions at √s = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider, corresponding to an integrated luminosity of 139 fb−1. Four signal regions, with the requirement of at least three light leptons (electron or muon) and at least two jets out of which at least one jet is identified as coming from a b-hadron, are considered based on the number of leptons of a given flavour. The main background processes are estimated using dedicated control regions in a simultaneous fit with the signal regions to data. No excess above the Standard Model background prediction is observed and 95% confidence level limits on the production cross section times branching ratio are derived as a function of the leptoquark mass. Under the assumption of exclusive decays into te− (tμ−), the corresponding lower limit on the scalar mixed-generation leptoquark mass mLQd mix is at 1.58 (1.59) TeV and on the vector leptoquark mass mU˜1 at 1.67 (1.67) TeV in the minimal coupling scenario and at 1.95 (1.95) TeV in the Yang–Mills scenario

Measurements of the production cross-section for a Z boson in association with b- or c-jets in proton–proton collisions at √s = 13 TeV with the ATLAS detector

This paper presents a measurement of the production cross-section of a Z boson in association with bor c-jets, in proton–proton collisions at √s = 13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of 140 fb−1. Inclusive and differential cross-sections are measured for events containing a Z boson decaying into electrons or muons and produced in association with at least one b-jet, at least one c-jet, or at least two b-jets with transverse momentum pT > 20 GeV and rapidity |y| < 2.5. Predictions from several Monte Carlo generators based on next-to-leading-order matrix elements interfaced with a parton-shower simulation, with different choices of flavour schemes for initial-state partons, are compared with the measured cross-sections. The results are also compared with novel predictions, based on infrared and collinear safe jet flavour dressing algorithms. Selected Z+ ≥ 1 c-jet observables, optimized for sensitivity to intrinsic-charm, are compared with benchmark models with different intrinsic-charm fractions

Search for heavy Majorana or Dirac neutrinos and right-handed W gauge bosons in final states with charged leptons and jets in pp collisions at √s = 13 TeV with the ATLAS detector

A search for heavy right-handed Majorana or Dirac neutrinos NR and heavy right-handed gauge bosons WR is performed in events with energetic electrons or muons, with the same or opposite electric charge, and energetic jets. The search is carried out separately for topologies of clearly separated final-state products (“resolved” channel) and topologies with boosted final states with hadronic and/or leptonic products partially overlapping and reconstructed as a large-radius jet (“boosted” channel). The events are selected from pp collision data at the LHC with an integrated luminosity of 139 fb−1 collected by the ATLAS detector at √s = 13 TeV. No significant deviations from the Standard Model predictions are observed. The results are interpreted within the theoretical framework of a left-right symmetric model, and lower limits are set on masses in the heavy righthanded WR boson and NR plane. The excluded region extends to about m(WR) = 6.4 TeV for both Majorana and Dirac NR neutrinos at m(NR) < 1 TeV. NR with masses of less than 3.5 (3.6) TeV are excluded in the electron (muon) channel at m(WR) = 4.8 TeV for the Majorana neutrinos, and limits of m(NR) up to 3.6 TeV for m(WR) = 5.2 (5.0) TeV in the electron (muon) channel are set for the Dirac neutrinos. These constitute the most stringent exclusion limits to date for the model considered

Deep generative models for fast photon shower simulation in ATLAS

The need for large-scale production of highly accurate simulated event samples for the extensive physics programme of the ATLAS experiment at the Large Hadron Collider motivates the development of new simulation techniques. Building on the recent success of deep learning algorithms, variational autoencoders and generative adversarial networks are investigated for modelling the response of the central region of the ATLAS electromagnetic calorimeter to photons of various energies. The properties of synthesised showers are compared with showers from a full detector simulation using geant4. Both variational autoencoders and generative adversarial networks are capable of quickly simulating electromagnetic showers with correct total energies and stochasticity, though the modelling of some shower shape distributions requires more refinement. This feasibility study demonstrates the potential of using such algorithms for ATLAS fast calorimeter simulation in the future and shows a possible way to complement current simulation techniques

Search for doubly charged Higgs boson production in multi-lepton final states using 139 fb−1 of proton–proton collisions at s√ = 13 TeV with the ATLAS detector

A search for pair production of doubly charged Higgs bosons (H±± ), each decaying into a pair of prompt, isolated, and highly energetic leptons with the same electric charge, is presented. The search uses a proton–proton collision data sample at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 139 fb−1 recorded by the ATLAS detector during Run 2 of the Large Hadron Collider (LHC). This analysis focuses on same-charge leptonic decays, H±±→ℓ±ℓ′± where ℓ,ℓ′=e,μ,τ, in two-, three-, and four-lepton channels, but only considers final states which include electrons or muons. No evidence of a signal is observed. Corresponding upper limits on the production cross-section of a doubly charged Higgs boson are derived, as a function of its mass m(H±±), at 95% confidence level. Assuming that the branching ratios to each of the possible leptonic final states are equal, B(H±±→e±e±)=B(H±±→e±μ±)=B(H±±→μ±μ±)=B(H±±→e±τ±)=B(H±±→μ±τ±)=B(H±±→τ±τ±)=1/6, the observed (expected) lower limit on the mass of a doubly charged Higgs boson is 1080 GeV (1065 GeV) within the left-right symmetric type-II seesaw model, which is the strongest limit to date produced by the ATLAS Collaboration. Additionally, this paper provides the first direct test of the Zee–Babu neutrino mass model at the LHC, yielding an observed (expected) lower limit of m(H±±) = 900 GeV (880 GeV)

Constraints on spin-0 dark matter mediators and invisible Higgs decays using ATLAS 13 TeV pp collision data with two top quarks and missing transverse momentum in the final state

This paper presents a statistical combination of searches targeting final states with two top quarks and invisible particles, characterised by the presence of zero, one or two leptons, at least one jet originating from a b-quark and missing transverse momentum. The analyses are searches for phenomena beyond the Standard Model consistent with the direct production of dark matter in pp collisions at the LHC, using 139 fb−1 of data collected with the ATLAS detector at a centre-of-mass energy of 13 TeV. The results are interpreted in terms of simplified dark matter models with a spin-0 scalar or pseudoscalar mediator particle. In addition, the results are interpreted in terms of upper limits on the Higgs boson invisible branching ratio, where the Higgs boson is produced according to the Standard Model in association with a pair of top quarks. For scalar (pseudoscalar) dark matter models, with all couplings set to unity, the statistical combination extends the mass range excluded by the best of the individual channels by 50 (25) GeV, excluding mediator masses up to 370 GeV. In addition, the statistical combination improves the expected coupling exclusion reach by 14% (24%), assuming a scalar (pseudoscalar) mediator mass of 10 GeV. An upper limit on the Higgs boson invisible branching ratio of 0.38 (0.30+0.13−0.09) is observed (expected) at 95% confidence level