Authors :

Molle, Fran็ois ; Chompadist, C.; Srijantr, T. and Jesda Keawkulaya. 2001.

This research had been funded by the European Union, through its INCO-DC Project

Summary :

The Chao Phraya River Basin (one third of Thailand but 70% of its GDP) is now facing unprecedented challenges regarding the status of its water resources. Existing water storage facilities are insufficient to fully realise the potential for production in the dry-season and new water resource development projects are facing financial and environmental constraints. There is increased awareness that both surface and underground water are not properly monitored and the concerned agencies are not empowered with sufficient technical, human and legal means to control these different uses. This translates into high externalities (shortages, pollution and land subsidence) and patterns of distribution characterised by uncertainty and low levels of equity. Despite the temporary respite brought about by the 1997 economic crisis, projections for the mid-term show dramatic consequences and confirm that drastic measures are needed. In other words, what is at stake is the proper management of the transition from a status of common-pool resources in sparsely populated agricultural areas to one of a collective management of more complex and closed river basins, respectful of basic equity and efficiency standards.

This report first analyses the current situation regarding water allocation in the dry-season and attempts to understand evolutions and to identify bottlenecks.

þ Water accounting in the dry season for the Chao Phraya Delta shows that very little unproductive water is lost out of the system. This includes evaporation in waterways and evapotranspiration in fallow lands, and the amount of water which flows to the sea in excess of what is necessary to control pollution and saline intrusions. Infiltrations to shallow aquifers are re-used by tube wells, while those to deep aquifers are tapped by deep wells in Bangkok Metropolitan Area (BMA). Most drains are gated or supply downstream areas. Altogether, it is estimated that only 12% of controlled supply (dam releases, transfer from Mae Klong Basin and underground water) is lost, pointing to an overall macro efficiency of 88%. If evaporation losses in the two storage dams are computed, this rate decreases to 83%. This situation is typical of 'closed systems', where demand exceeds supply and reuse of water is high.

þ A prospective analysis of the supply and demand in the basin indicates that the amount of water available for dry-season agriculture is bound to decline drastically over the next two decades. This far-reaching trend results from both the decline of the inflow in the Bhumipol and Sirikit Dams (due to growing abstraction and climatic change in the upper basin) and from the growth of urban areas, particularly BMA. This forecasted evolution will materialise more rapidly if the growth rate of BMA is high, but it is shown that in all instances the decline is likely to be much higher than any gain or savings which could be made by improving the current situation. In other words, there remains little doubt that however desirable these improvements may be, supply will have to be augmented in the mid-run. Projections show that with a growth of non-agricultural water use (principally BMA) at 5% per year, the average available water for agriculture in the dry-season will decline from 4.6 billion m³ in 2000 to under 3.0 billion m³ (Bm3) in 2015 (all other parameters being constant).

þ Dry-season cropping had significantly changed in many respects over the last quarter of century. It increased in magnitude and expanded in both the middle basin (lower Ping, lower Nan) and the delta. The total cropping intensity over the 1977-99 period was estimated at 1.45 but was as high as 1.63 in the last 5 years. Several historical constraints have been removed to allow the growth of DS cropping:

1. some canals were dredged or recalibrated, allowing larger flows;
2. farmers offset the difficulty of having gravity inflow into their canal or ditch by acquiring impressive individual and mobile pumping capacities;
3. secondary water sources were developed or tapped (wells, ponds, drains);
4. shorter rice varieties (as short as 90 days) have become common;
5. transplanting, and its constraints in timing and scheduling, gave way to a more flexible technique (wet broadcasting); harvesting is now widely mechanised, easing calendars and labour force constraints;
6. on-farm development gradually expanded (farmers’ investments);
7. calendars were de-regulated to adapt to fluctuating conditions of supply (western upper delta) and of the flood regime (west bank).

An average value of the cropping area in the dry season is 3 million rai (of rice-equivalent) with 60% in the lower delta and 40% in the upper delta. In the last 5 years records have been beaten, with a high of 4.9 million rai in 1998. This corresponded to a surge of triple cropping, recorded at 1 million rai.

þ But spatial patterns of allocation show a significant inequity between the western and the eastern parts of the upper delta, and more generally between Projects.

The average cropping intensity by Project, taking into account only the area with on-farm conditions allowing the cultivation of High Yield Varieties in the dry-season, was found to vary widely (from 1.07 to 1.88). The lower delta (conservation area) is at an advantage because canal water is available to farmers with little possible control by RID. In the upper delta, the western region is found to enjoy higher cropping intensities, partly because of political interventions, partly because of tube wells (upper area), and land consolidation (preferential allocation, formerly justified by the fact that the farmers concerned had to pay back part of the costs).

þ The analysis of the year 1998 showed a very complex spatial pattern in the spread of cropping areas. In contrast with the official dry-season calendar starting in February, it could be seen that the western part of the upper delta started cropping as early as November. More generally the de-regulation of cropping calendars was analysed and understood as a strategy to save water and to gain access to water, in particular by forcing RID to supply already established crops with irrigation water. In the dry-season 1998, only 23% of the upper-delta did not grow a second rice crop, against 44% with double-cropping, 9% with triple cropping (7% with non rice-crops, and 15% of non-agricultural areas).

A striking observation was that a significant part of the flood-prone area (planted with traditional varieties in the wet season), initially disregarded by planners and managers, could achieve dry-season cropping. This was allowed by an endogenous development of on-farm facilities.

þ The current method of water allocation was investigated and appeared as supply-driven, guided by experience rather than by clear-cut technical parameters, somewhat flexible rather than rigidly pre-determined. It focuses on the allocation at the macro level, with little control on the day-to-day fluctuations experienced at the lower levels but with a concern not to stray too much from the weekly planning, as a way to ensure that the total water released at the end of June does not differ from the overall target by, say, more than15%. Adjustments in the planned schedule are sometimes necessary to respond to sharp imbalances between the planned and effective crop progress, to climatic events or political interventions.

The main point under consideration was how the targets (volume released and cropping areas) were defined, based on the available water volume at the beginning of the dry-season. Insufficient security carry-over stocks at the end of the dry season make the system vulnerable to exceptionally dry wet-seasons, when the net gain in stored water can be as low as 1.5 Bm3. The 1980, 1994 and 1999 crises were analysed and it was shown that they resulted from the inability to cut dry-season water supply in-line with security standards. Attributing the responsibility of water shortage to poor efficiency is the most widespread and misleading misconception. Should irrigation gain 10% in efficiency, this would not diffuse any crisis but only raise, by the same amount, the area that would be irrigated (as supply is to remain far under the overall potential demand). Shortages and crises are not due to an hypothetical low efficiency but to the allocation policy and its impact on dam water stocks when risk has been mis-evaluated. The lack of strong technical criteria in managing dams and in allocating water to irrigation, and the way they are being challenged by political interventions and farmers’ uncontrolled planting, are conducive to recurrent shortages and incur escalating risk. This does not dismiss the fact that efficiency gains are desirable, in that they allow the benefits of water use to be spread to a larger number of users, but it draws our attention to the inconsistency of the commonly stated relationship between efficiency and water shortage.

þ An attempt was made to estimate the amount of water released by the dams and further lost to the sea (in excess of what is necessary to control salinity). This is a controversial question as EGAT is often accused of using huge amounts of water only for the sake of energy generation, which depletes the water stocks available for agriculture. The total average yearly loss was found to be quite considerable, amounting to 2.9 Bm3, or 30% of the average inflow in the two dams. However, most of the years with high “lossesâ€� were early years in which a significant share of the Thai energy generation system was based on hydroelectricity. In the 1990s, on the other hand, as the Chao Phraya system gradually “closedâ€� and water resources came under stricter scrutiny, such losses were under 1 Bm3/year, with the exception of the year 1996 which stands as a horrendous counter-example and serves to stress that regulative measures are needed in order to avoid such occurrences.

þ Extensive farm surveys in three villages with contrasting access to water in the dry-season were conducted to show the impact of such an access on the sustainability of farming systems in the delta. Dramatic differences in cropping intensity and land productivity between the three villages were observed. Despite a relative re-balancing of average incomes thanks to animal breeding and non-agricultural work opportunities, this strengthens the necessity to give due attention to existing allocation imbalances, in particular to give more consideration to those areas which grow deep water rice in the wet season but have adequate on-farm development to also grow a crop in the dry season.

Based on these analyses, several measures and recommendations could be established.

þ Water scarcity can be partly solved by tapping additional local water sources. A brief mention is made of the development of individual tube-wells and public reservoirs in low lands. Shallow aquifers are already intensively exploited where they are accessible and of good quality (the upper delta and Mae Klong area) and there is little scope for expanding farmers pumping capacity. The policy to excavate huge public reservoirs in natural swamps and low lying public land was scrutinised through a case study in Ayutthaya Province. It was shown that it is far from certain that farmers will use these reservoirs, and that many factors must be considered before engaging in such well-intentioned but costly investments.

þ Increasing efficiency in the irrigation sector is a returning 'red herring'. Unqualified insistence on very low efficiency (30%) is both misleading when adopting a basin wide vision and erroneous when applied to the distribution of irrigation water. It can be shown that a rai of rice consumes on the average 1,500 m³/rai , for an average plant consumptive use of 980 m³/rai, with 210 m³/rai supplied by rainfall, which gives an overall irrigation efficiency of 60%, a rather high figure as far as gravity irrigation is concerned. The efficiency in the lower delta is significantly higher than this value, but the opposite is true regarding the upper delta.

Rather than focusing on illusory gains at the plot level, gains in efficiency can be obtained by reducing the amount of water effectively consumed by the plant. This can be done either by giving more attention to cropping calendars or by adopting non-rice crops.

It was shown that the evolution of climatic parameters along the year (ET and rainfall), to which must be added the residual soil moisture, significantly impacts on crop water requirements. De-aggregating dry-season cropping calendars and promoting early and late calendars, instead of sticking to the conventional season starting in February, leads to sizeable water savings (up to 10%). This path has been shown by the farmers themselves and must be incorporated in a new definition of cropping calendars by sub-areas.

Diversification out of rice to field crops is a popular refrain at least as far back as the 1960s. As long as the economic environment of field crop production remains unattractive and uncertain, there is little incentive for farmers to adopt such crops and scope to sustain criticism on their growing rice, as many have incurred in losses by growing field crops (either by will or by suggestion from extension services). Inducing shifts in cropping patterns to achieve water saving by means of differential taxes is believed to be unrealistic while such risk remains. In addition, there are several other constraints (agro-ecology: heavy soil with little drainage, not favourable to growing field crops; labour and capital requirements, skill-learning, development of proper marketing channels, etc.), which condition the process of diversification and it is doubtful that, in addition to public policies aimed at fostering it, its pace may be increased much beyond what is already observed. Farmers do not need to have their water priced to shift to other productions. They will increasingly do so if uncertainty on water supply and prices is lowered.

þ Demand management options and its emphasis on cost recovery and sectorial allocation was also analysed with regards to the Chao Phraya Basin context. It was shown that the central water allocation system had handled relatively well the issue of allocating water to activities with higher economic return, and that the assumed 'lion share' of agriculture eventually was the (fluctuating) leftover water in the system. With reduced scope for achieving water savings or economic reallocation, concepts of water charge or water markets lose most of their appeal. In addition, their application would be critically constrained by several practical aspects: a high heterogeneity in the access to water, and in the social cohesion of farmers (which precludes strong collective arrangements); the lack of control over water at the basin level, of metering and conveyance facilities; and the presence of numerous small-scale users difficult to identify. Cost recovery also appeared as a questionable objective, when seen in the wider national context of taxation and subsidisation. The alleged 'huge drain' of Operation and Maintenance costs amount to 0.16% of the national income and it would probably not be difficult to identify other larger 'drains' with much less social and economic benefits.

However, the 'virtuous' linkage existing between structural, managerial, institutional and financial approaches is recognised, with the pricing of water considered as a mere element of contractual binding between RID and groups of users. It can be seen as a reinforcing factor in a participatory process in which users would be brought into the decision making process regarding allocation and management. Such a reform was outlined but emphasis was placed on the existing gap between its prerequisites and the current situation. Defining a ‘service’ or ‘a right’ is probably both the most important prerequisite and the major difficulty. The actual lack of control over the system (which includes technical, institutional and political aspects) does not allow reliable scheduling and causes widespread heterogeneities in the access to water (in terms of quantity, quality, timing, and water level).

þ Energy generation and dam management must be adapted to changing conditions. With a contribution of Bhumipol and Sirikit Dams, each between 1 and 2% of Thai energy generation, there is no more justification to use dam water for the sole purpose of electricity generation, given the high socio-economic value of water for agriculture and rural livelihood. In addition, peak requirements generation, usually ensured by dams because of the facility of switching turbines on and off, can now be widely ensured by gas turbines and other dams (in Laos, and dams in surplus basins, such as the Mae Klong Basin). This calls for a formalisation of the priority of downstream uses, in order to avoid occasional huge wastes, as in 1996.

The declining importance of dams in energy generation must also be acknowledged and open the way to the possibility of using dam dead storage volumes when necessary. Public awareness campaigns are needed to avoid psychological side effects and to present this situation as normal, even though it must remain exceptional. The dead storage of the Sirikit Dam is more than enough to cover incompressible needs for 2 or 3 months in case of emergency. No crisis should be allowed to occur with nearly 3 Bm3 of unused water.

However, even the probability of a crisis period can be (and should be) easily reduced by applying strict standards on carry-over security stocks. It was a political failure to limit dry-season releases which generated the crises of the 1990s, not the lack of water per se. It can be shown that setting and enforcing target releases to ensure a stock of 2.5 Bm3 on the 1^st of July is enough to avert crises.

Other aspects of dam management which require attention are the setting of the upper-rule curve according to a criteria of maximisation of water stocks (under constraints of dam safety) and not of maximisation of energy, and the improvement of the responsiveness to hydrological events, principally rainfall in the wet-season.

þ The allocation process must be reconsidered in order to allow more equity and to raise security standards. This includes:

1. De-aggregation of DS cropping-calendars and the formal (and official) recognition of the interest of shifting part (the western part) ahead in time (November);
2. a growing effective concern to incorporate more equity in the total amount allocated to different sub-areas (more to the east);
3. the recognition that a growing part of the flood-prone area is now fit to accommodate HYV in the dry-season and should also be considered,
4. curtailing triple-cropping by stricter scheduling in order to spread the benefit of double-cropping;
5. fixing targets with due consideration to the security stocks to be ensured at the end of each season.

These measures can be taken even within the top-down allocation system but it is recognised that current political and institutional constraints do not allow a thorough rebalancing (bottom-up re-allocation): this could be achieved if a Chao Phraya Basin Organisation was set up to control water allocation in the different parts of the basin, and to initiate a participatory process with concerned stakeholders in order to: 1) define an overall policy of water allocation; 2) to define the plan to be implemented each year; 3) to have concerned users participating in the monitoring of effective deliveries. This is contingent upon a process of identification and empowerment of user representatives and is at the core of a much more complex long-term institutional reform.

Overall, it is clear that efficiency concerns are poorly addressed by and offer little justification to proposals of water pricing or water markets, and that there is limited scope to achieve large water savings. The different possible measures proposed are not likely to radically revert the current water short status of the Chao Phraya Basin. As regards to equity considerations, it is not sure that imbalances be sufficient to justify costly and complex institutional reforms which success is not at all ensured. The return of water crises can be best interpreted as the expression of the refusal by the farming sector to see its share declining. The mismatch between supply and demand is at present dealt with by eliciting releases – through political channels - beyond what risk standards command. The current vulnerability of the overall system can only be done away if the growing water scarcity is fully passed on to users. This has strong political implications and it can be hypothesised that a mounting pressure on water would translate in unrest in rural areas, therefore in more political interventions and more support for water resource development.

It is beyond doubt that a sweeping reform of the administrations and of the legislation involved is needed. However, because of the lack of political support to achieve such reforms (as shown by the stalled process of the water law), it was found more adequate to separate recommendations in two scenarios. The first one is a “low� scenario, which produces significant but partial benefits, and does not rest on the prerequisite of a large-scale institutional reform covered by a new water law. It combines structural improvements and innovations in management.

The second scenario, on the contrary, assumes that the current institutional gridlock is overcome and that a proper Chao Phraya Basin Organisation allows for the empowerment of users and their active participation in the main decision processes: allocation of water within the delta and at the different lower levels, including scheduling and maintenance. Water pricing can be introduced as a “virtuous� binding element between users and suppliers, if conditions for defining contractual services, and in the long term, rights, are fulfilled.

Keywords :

Water allocarion, watter management, cropping intensity, water balance, water policy, Thailand.

Contacts :

Francois Molle
francois.molle@ird.fr