Pond Depth Research Articles

Climate change-related risk adaptation in striped catfish, tilapia and shrimp farming systems in the Mekong Delta, Vietnam

This study aims to determine climate change-related risk (CCR) impacts, responses of farmers, and assistant activities in tilapia cage culture (TC), striped catfish nursery (SCN), striped catfish grow-out (SCG), improved extensive shrimp (IES) and intensive shrimp (IS) systems. A survey of 601 farmers in the Mekong Delta, Vietnam, was conducted using clustered sampling. Intense rainfall events and rapid changes in temperature affected all five surveyed farm systems. Extreme high temperatures impacted the TC, IES and IS systems, while extreme low temperatures impacted the striped catfish groups (SCN and SCG). Striped catfish farming systems were more sensitive to low temperatures in comparison to shrimp and tilapia. For risk management purposes, increasing pond dike height was applied in the SCN and SCG farming systems. While increased pond depth was observed in the SCN, SCG and IS systems, the IS and SCN systems had higher counts of additional pond construction. Water quality was monitored and feed supplements/medicines were used by farmers in all five farm systems; however, these activities were higher for the SCN, SCG and IS systems than for the TC and IES groups. Reduced stocking density was observed in TC, SCN, SCG and IS, but not in IES. In addition, the use of aerators or mixers was the most-employed solution in the IS system. Amongst information sources of climate-related risks, television was found to be the most important, followed by neighbouring farmers and the Department of Fisheries (DOF)...

Impact of the Intermittency Movement of Center Pivots on Irrigation Uniformity

A computer model was developed to simulate the varying depths of water applied to the ground due to the intermittent movements of a typical center pivot. The stop–go model inputs include the sprinkler application depth, the sprinkler pattern, that pattern’s wetted radius, the center pivot’s % timer setting, the move cycle time, and the end tower maximum travel speed. The model outputs were the depth of application in the pivot’s movement direction, the distribution uniformity (DU), and the coefficient of uniformity (CU). The results revealed that the pivot circular application uniformity is mostly a function of the move distance as a percent of the sprinklers’ wetted radius. This, in turn, is a function of the percent timer setting, the cycle time, and the end tower travel speed. Due to this, the high-speed center pivots had corresponding lower application uniformities compared to low-speed machines, and sprinklers with larger wetted radii resulted in better uniformity. Shortening the cycle time also resulted in higher uniformity coefficients. Based on these results, it is recommended that the run time be set based on the pivot end-tower’s travel speed and sprinkler wetted radius, such that the end tower move distance is equivalent to the sprinkler wetted radius. This will reduce wear to the tower motors due to the on–off cycling, especially for slow travel settings and for sprinklers with larger wetted radii. The ponding depths at different percent of the move distance, for the potential runoff, were estimated, which were set to be equivalent to the wetted radius.

STUDI KETINGGIAN KOLAM RETENSI SIMPANG POLDA PALEMBANG UNTUK LANGKAH PENENTUAN KEBIJAKAN

Simpang Polda retention pond is an alternative flood control construction which is designed to temporarily hold exceeding water flow during rainfall in the vicinity of Simpang Polda, in order to avoid or reduce flood in the area. Retention ponds are prone to sedimentation due to garbage and other materials settling down in the bottom of the pond, which in turn causing reduction of total volume of water it can contain. To ensure that the pond has enough volume, depth measurements were done so that the pond can function as intended. Boat robots from previous research in 2019 and 2020 were utilized as the method to measure the depth of the retention pond. The boat robots mapped the depth of the whole pond area with the help of remote control and single beam sensor. Measurement result shows that the Simpang Polda retention pond has an average depth of 2.245 m. Based on this finding it is suggested that the local government water resource management agency (Dinas PUPR Dept. PSDA) to follow up with the appropriate sediment removal procedures to return the pond’s depth back to the original value when it was constructed

Performance study of open pond as heat sink of water-cooled air conditioner

In this paper, performance of open pond as heat sink of water-cooled condenser instead of cooling tower was considered. Experimental test of a 3.5 kW R32 air conditioner with 3m×3m×1.1 m open pond was performed and the unit was running between 8 a.m. and 6 p.m. on a clear sky day in summer of Chiang Mai, Thailand. A model to predict the average pond temperature and energy efficient ratio (EER) of the air conditioner was developed and the simulated results agreed well with those of the experiments. The model was used to find out the suitable pond volume that could keep the air conditioner EER over 4.1 when the number of air-conditioner were changed from 1 to 3 units on the hottest day in April. By adjusting the appropriate ratio of pond surface area and pond depth (A/D), the pond temperature on the next day could be lower or equal to that on the previous day then the air-conditioner EER should be at least similar to that on the previous day.

Supplementary irrigation for managing the impact of terminal dry spells on the productivity of rainfed rice (Oryza sativa L.) in Fogera Plain, Ethiopia

A terminal dry spell is one of the main limiting factors for rice productions. Therefore, this study was conducted to assess the effect of supplemental irrigation for managing the impact of terminal dry spells on the productivity of different rice varieties grown under rainfed conditions in the Fogera Plain. The experiment was designed in a split-plot design with water regimes as main plot factors and rice varieties as a subplot factor with three replications. The water regimes were: dry planted rainfed rice (farmers practice) (FP), transplanted but not irrigated (IWOI), transplanted and irrigated to saturation (SAT), transplanted and ponding to 1 cm water (PD1), and transplanted and ponding to 3 cm water (PD2). The rice varieties were: X-Jigna (V1), Edget (V2), Hiber (V3), Fogera-1 (V4), and Nerica-4 (V5). The combined effect of PD2 with V1 had the highest grain yield (t/ha) (4.35 t/ha) while FP with V3 had the lowest grain yield (2.12 t/ha). The highest (205%) relative grain yield was obtained when V1 was grown under PD2 followed by V4 under PD2 (199%) and V5 under PD2 (192%) compared to FP with V3. Irrigation water productivity (WPIR) varied between water regimes x varieties from as low as 1.84kg grain mm−1ha−1 for V3 in FP to as high as the yield of 3.07kg grain mm−1ha−1 for V1 in PD2. The highest and lowest net benefits were recorded for V1 grown under PD2 (65, 550 ETB) and for V3 grown under TWOI (33, 500 ETB ha−1), respectively. Hence, the combined application of 3 cm ponding depth (PD2) with X-Jigna (V1) and 1cm ponding depth with Fogera-1 (V4) rice varieties could be suggested as effective terminal stress management to increase the yield and profitability of rainfed rice in the Fogera Plain and similar agro-ecologies.

Modeling Seasonal Performance of Operational Urban Rain Garden Using HYDRUS-1D

Accounting for seasonal effects on rain garden performance can be challenging in colder regions. Changes in temperature cause changes in the viscosity of water, infiltration rates, and evapotranspiration rates. A variably saturated hydrologic model (HYDRUS-1D) was calibrated and validated using observed ponding depth and soil moisture data from two different storm events for a rain garden owned and operated by the Philadelphia Water Department (PWD). Warm and cold seasons were simulated with typical meteorological data and temperature-adjusted saturated hydraulic conductivity values. Design storm simulations confirmed that the rain garden is over-performing. By increasing the loading ratio (i.e., the ratio of drainage area to rain garden footprint) in the model, the maximum capacity of the rain garden was estimated to be 43% more than the design in the cold season, and 110% more than that in the warm season. If the maximum allowable ponding was raised to accommodate more water depth, the rain garden could have a maximum capacity 205% larger than the design while still meeting the PWD’s 24-h drain down requirement. This study demonstrates (1) how to develop a simple one-dimensional (1D) model that can reasonably account for seasonal effects on rain garden performance; and (2) the use of this model to quantify system capacity year-round and ultimately inform regulations and design.

MICROCRUSTACEAN ASSEMBLAGES AND WATER QUALITY IN A HIGH-ALTITUDE POND IN SOUTH BRAZIL (PARANÁ)

The aim of this study was to assess the abundance and richness of microcrustacean, and water physical and chemical characteristics of a high-altitude pond in the Serra do Mar at State of Paraná. Water samples were collected quarterly between August 2015 and August 2016. Environmental conditions of pond were characterized by small pond size and depth, cold and well oxygenated water, and neutral or slightly acid pH. Mean total microcrustacean density was 945.0 ind m-3, whereas total taxon richness was 3.40. The most abundant species was Tropocyclops prasinus. The small size and the isolament of the pond, and the low temperatures were related to the low species richness and abundance. This study is unprecedented to the State of Paraná. Future studies attempt to understand the environmental conditions and distribution of microcrustaceans from high-altitude ponds.

Parameterization and modeling of paddy rice (Oryza sativa L. ssp. japonica) growth and water use in cold regions: Yield and water-saving analysis

Rice is the high-water consumption crop that feeds more than half of the world population. The planting area of cold region rice is expanded rapidly in recent years due to the high market values, also resulting in increasing water shortages and eco-environmental problems on a regional scale. Pursuing high benefits and increasing water use efficiency become more significant both for stakeholders and managers. To understand the yield variation and water-saving potential, the specific rice model-ORYZA2000 was adopted to predict the responses of rice growth/yield and water use to the various climatic and irrigation conditions in a typical cold region of northeast China. Field experiments were conducted for the Japonica rice in cold regions (JRC) during 2018 and 2019, with detailed observations on rice growth and development. The ORYZA2000 was calibrated and validated using two-year experimental data. Simulated ponded water depth, various organ development and yield fitted well with field observations. A set of recommended values of crop parameters for JRC was obtained through the systematic parametrization, showing very specific and different characters from the varieties in warmer regions. The irrigation scheduling module was modified for adapting to the various irrigation regimes. After that, the scenario simulation with 30-year different climatic data (i.e. 1990–2019) and three different irrigation regimes (i.e. traditional flood irrigation (TFI), shallow-wet irrigation (SWI) and controlled irrigation (CTI)) were conducted using the calibrated model. Status evaluation and scenario analyses indicated that the crop yield of JRC varied significantly due to relatively large fluctuations of photothermal conditions in different years. The inter-annual potential yield varied from 6790 to 9516 kg ha−1, with an average of 8210 kg ha−1. Evaluation on water-saving scenarios indicated that adopting SWI and CTI regimes could averagely save up to 90 mm and 140 mm (20% and 30%) of irrigation water in dry years, respectively, compared with TFI regime. Overall, the obtained set of parameters for JRC could efficiently complement the parameter database for rice modeling in cold regions; meanwhile, the yield and water-saving evaluation could provide very useful information and the basis for supporting the future JRC production and water-saving management.

Building resiliency to climate change uncertainty through bioretention design modifications

Climate stationarity is a traditional assumption in the design of the urban drainage network, including green infrastructure practices such as bioretention cells. Predicted deviations from historic climate trends associated with global climate change introduce uncertainty in the ability of these systems to maintain service levels in the future. Climate change projections are made using output from coarse-scale general circulation models (GCMs), which can then be downscaled using regional climate models (RCMs) to provide predictions at a finer spatial resolution. However, all models contain sources of error and uncertainty, and predicted changes in future climate can be contradictory between models, requiring an approach that considers multiple projections. The performance of bioretention cells were modeled using USEPA's Storm Water Management Model (SWMM) to determine how design modifications could add resilience to these systems under future climate conditions projected for Knoxville, Tennessee, USA. Ten downscaled climate projections were acquired from the North American Coordinated Regional Downscaling Experiment program, and model bias was corrected using Kernel Density Distribution Mapping (KDDM). Bias-corrected climate projections were used to assess bioretention hydrologic function in future climate conditions. Several scenarios were evaluated using a probabilistic approach to determine the confidence with which design modifications could be implemented to maintain historic performance for both new and existing (retrofitted) bioretention cells. The largest deviations from current design (i.e., concurrently increasing ponding depths, thickness of media layer, media conductivity rates, and bioretention surface areas by 307%, 200%, 200%, and 300%, respectively, beyond current standards) resulted in the greatest improvements on historic performance with respect to annual volumes of infiltration and surface overflow, with all ten future climate scenarios across various soil types yielding increased infiltration and decreased surface overflow compared to historic conditions. However, lower performance was observed for more conservative design modifications; on average, between 13-82% and 77–100% of models fell below historic annual volumes of infiltration and surface overflow, respectively, when ponding zone depth, media layer thickness, and media conductivity were increased alone. Findings demonstrate that increasing bioretention surface area relative to the contributing catchment provides the greatest overall return on historic performance under future climate conditions and should be prioritized in locations with low in situ soil drainage rates. This study highlights the importance of considering local site conditions and management objectives when incorporating resiliency to climate change uncertainty into bioretention designs.

Ciliofauna Species Wealth of the Khabarovsk Central City Pond

The paper describes the composition of the Ciliata species of the Khabarovsk Central Pond. In the course of the inventory, 43 Ciliata species belonging to 2 subtypes and 11 classes have been identified, the most numerous of which are Spirotrichea and Oligohymenophorea. Also, 20 species have not previously been recorded on the territory of the Middle Amur Region. By the frequency of occurrence, the vast majority of species (23 representatives) are observed in the solitary samples (up to 15 %). The background species include ciliates such as Coleps hirtus, Strombidium viride, Stylonychia mytilus complex, Paramecium caudatum, and Uronema marinum. It has been found that in the reservoir being studied, the average size (up to 200 μm) ciliates dominate. By the ecotope preferred, the ‘transitional’ cluster representatives prevail, which indicates the possible widespread colonization of the reservoir by protozoa. This is due to the shallow depth of the Central Pond and, therefore, the lack of clear boundaries between individual zones.

Study on bioretention for stormwater management in cold climate, Part I: Hydraulics

Simulated storm events were applied to four large bioretention columns to approximate 1.6 years of equivalent volume in Edmonton, Alberta’s typical climate. Summer, winter, and spring runoff were simulated in temperature-controlled laboratories with a range of −20 °C to +20 °C. During summer less porous bioretention media (i.e. loam soil) effectively weakened peak flows by >83% for 1:2 year events while more porous bioretention media (i.e. sandy loam soil) maintained hydraulic conductivities >9.1 cm/h. Winter operation consisted of all columns being subjected to −20 °C and then 1 °C repeatedly. Events were applied at an air temperature of 1 °C and, although frozen initially, more porous media experienced faster water breakthrough and ponding disappearance in winter indicating that hydraulic performance during intermittent warming periods in winter may be achievable. All columns’ hydraulic performance rebounded quickly in the subsequent summer. All columns successfully managed 1:2 year events in terms of infiltration rate, ponding depth and duration. Preliminary results also showed that both media have the potential to manage less frequent (1:5 and 1:10 year) events.

Optimizing micro-algae production in a raceway pond with variable depth

<p style='text-indent:20px;'>We present a modified model of algae growth in a raceway pond with the additional feature of variable pond depth. This requires an additional state variable to model depth as well as additional control to allow for variable outflow. We apply numerical optimal control methods to this model and show that the lipid yield of the process can be increased by 67% compared to that obtained with a fixed pond depth.</p>

Illumination system for growth and net energy ratio enhancement of Arthrospira (Spirulina) platensis outdoor cultivation in deep raceway pond

One major problem found in open raceway ponds for algae production is the limited light penetrability, which means that the pond depth should not exceed 25–30 cm. This study aimed to use transparent light-scattering column (LSC) to enhance the brightness in the deeper level of a deep raceway pond. A maximum of 16 LSCs were immersed vertically in the testing pond, which was compared with a control pond without LSC. The results showed that the cultivation period to the stationary phase of the LSC pond was 4 days faster than that of the control pond. The biomass productivity and net energy ratio of the LSC pond were respectively found to increase by about 48.3% and 41.7%, while the water loss from evaporation decreased by about 13.6%. The overview from the results indicated that the environment can be conserved by means of reducing the energy, time and water for cultivation.

Comparison of faecal indicator and viral pathogen light and dark disinfection mechanisms in wastewater treatment pond mesocosms

This study compared light and dark disinfection of faecal bacteria/viral indicator organisms (E. coli and MS2 (fRNA) bacteriophage) and human viruses (Echovirus and Norovirus) in Wastewater Treatment Pond (WTP) mesocosms. Stirred pond mesocosms were operated in either outdoor sunlight-exposed or laboratory dark conditions in two experiments during the austral summer. To investigate wavelength-dependence of sunlight disinfection, three optical filters were used: (1) polyethylene film (light control: transmitting all solar UV and visible wavelengths), (2) acrylic (removing most UVB <315 nm), and (3) polycarbonate (removing both UVB and UVA <400 nm). To assess different dark disinfection processes WTP effluent was treated before spiking with target microbes, by (a) 0.22 μm filtration to remove all but colloidal particles, (b) 0.22 μm filtration followed by heat treatment to destroy enzymes, and (c) addition of Cytochalasin B to supress protozoan grazing. Microbiological stocks containing E. coli, MS2 phage, Echovirus, and Norovirus were spiked into each mesocosm 10 min before the experiments commenced. The light control exposed to all sunlight wavelengths achieved >5-log E. coli and MS2 phage removal (from ~1.0 × 106 to <1 PFU/mL) within 3 h compared with up to 6 h in UV-filtered mesocosms. This result confirms that UVB contributes to inactivation of E. coli and viruses by direct sunlight inactivation. However, the very high attenuation with depth of UVB in WTP water (99% removal in the top 8 cm) suggests that UVB disinfection may be less important than other removal processes averaged over time and full-scale pond depth. Dark removal was appreciably slower than sunlight-mediated inactivation. The dark control typically achieved higher removal of E. coli and viruses than the 0.22 μm filtered (dark) mesocosms. This result suggests that adsorption of E. coli and viruses to WTP particles (e.g., algae and bacteria bio-flocs) is an important mechanism of dark disinfection, while bacteria and virus characteristics (e.g. surface charge) and environmental conditions can influence dark disinfection processes.

Development and verification of integrated photoelectric system for noncontact detection of pavement ponding and freezing

The ponding water and ice on the road surface can cause degradation of skid resistance that seriously affects driving safety. In order to accurately detect road surface conditions, an integrated photoelectric system was developed composed of an infrared light-emitting diode and a phototransistor. Typical asphalt pavements such as AC-13, SMA-13, and OGFC-13 were selected to simulate four road surface conditions: dry, wet, ponding water, and ice. The voltage intervals for dry and wet surface conditions were proposed by the light intensity method. The functional relationships were established between the depth of ponding and the output voltage, the thickness of ice, and the output voltage, respectively. The noncontact detection system for pavement ponding and freezing was developed by the design of the hardware of real-time controller, the software of supervisory computer, and the shell of entire system. Then the system was verified in the field conditions. According to the test results, there was a good linear relationship between the ponding depth and the output voltage, while there was a quadratic parabolic relationship between the ice thickness and the output voltage. The detecting accuracy was 91.67% for the dry and wet surface conditions. The detecting errors of ponding depth for three different types of pavement surface were 0.248, 0.168, and 0.189, respectively; the detecting errors of the ice thickness for three different types of pavement surface were 0.219, 0.261, and 0.326, respectively. The errors were within a reasonable range, and the detecting accuracy of ponding depth is higher than that of ice thickness.

Modeling water consumption, N fates, and rice yield for water-saving and conventional rice production systems

Quantifying water consumption, nitrogen (N) fates, and crop yield is crucial in developing the best management practices for rice production systems. A 2-year field experiment was conducted in Taihu Lake region, China. The experiment consisted of water-saving controlled and conventional flooding irrigation regimes that are factorially combined with two N management practices (farmers’ N fertilization and site-specific N management). A simple surface ponding water layer component was incorporated into the original WHCNS (soil water heat carbon nitrogen simulator) model to simulate and comprehensively evaluate water consumption, N fates, and rice yield for water-saving and conventional rice production systems. Field experiment data, including surface water ponding depth, soil water content, runoff, runoff N loss, crop N uptake, and yield, was measured to test the improved model. Results showed agreement between the measured and simulated values of surface ponding water depth, soil water content, runoff, N runoff loss, ammonia volatilization, crop N uptake, and yield and simulated values agreed well, with average relative root mean squared error values of 24.0%, 9.3%, 26.1%, 20.9%, 21.3%, 7.9%, and 4.6%, respectively. Crop yield showed no significant difference under different water and N management practices. Compared with conventional flooding system, controlled irrigation saved 34.1% of irrigation water and greatly reduced nonproductive water consumption (evaporation + runoff + deep percolation) by 16.9%–20.0%, thus increasing the water use efficiency (WUE). Site-specific N management substantially reduced N losses from ammonia volatilization, leaching, denitrification, and runoff by 50.1%, 33.8%, 13.3%, and 42.7%, respectively, compared with those of the farmers’ N fertilization practice. These results indicated that the combination of controlled irrigation regime and site-specific N management regime reduced the water consumption, N losses, and N2O emission and increased WUE and N use efficiency.

Management Strategies for Nile Tilapia (Oreochromis niloticus) Hatchery in the Face of Climate Change Induced Rising Temperature

In the quest for appropriate management strategies for less egg production in Nile tilapia (Oreochromis niloticus) due to climate change induced increasing temperature, five treatments (T): shade with cloth over brood hapa (T1), increase in pond depth (T2), aeration (T3), combination of above three interventions (T4) and control (no intervention) (T5) were investigated in a commercial hatchery in Mymensingh, Bangladesh during April to September. Mean egg production in T1, T2, T3, T4 and T5 was 20488, 15369, 3596, 21021 and 3979 eggs/hapa, respectively. T1 was the best strategy considered due to efficiency and simplicity. In May T1, T2, T3, T4 and T5 produced highest 30859, 36119, 8997, 45876 and 5506 eggs/hapa at 29.69°C, 30.12°C, 29.96°C, 29.61°C, and 31.26°C temperature, respectively. The most suitable water temperature for highest egg production (20365 eggs/hapa) was 29-31°C. Egg production above 32°C was found to be very low (179 eggs/hapa). Suitable ranges of dissolved oxygen, pH, alkalinity, ammonia and turbidity for egg production were found to be 4.5-6.0 mg/L, 8.0-8.8, 105-150 mg/L, 0-0.5 mg/L and 15-35 cm, respectively. In high temperature months commercial fish hatcheries should use shed with cloth over brood hapa to produce higher amount eggs.

Study on Rule of Heavy Metal Cu2+ in Small and Medium-Sized Tailings Ponds under Rainfall-Evaporation-Transpiration Coupling

In order to research the heavy metal migration rule of small and medium-sized tailings ponds under the action of climate, vegetation and groundwater, this paper consider the rainfall-evaporation-transpiration and coupling effect of groundwater, establish the model of different dam height, slope ratio, permeability coefficient and migration time impact on the migration of heavy metals of tailings dam, applied to Geostudio software, based on the orthogonal design method of factors significant difference analysis and design method of the comprehensive factors analysis, make up the simulation of the tailings heavy metal pollutants concentration of Cu2+ migration law. The results show that the height of tailing dam is inversely proportional to the average migration velocity of pollutant Cu2+. The effect of slope ratio on migration concentration of Cu2+ pollutant in tailings pond is not significant. The permeability coefficient has a highly significant influence on the migration of heavy metal Cu2+. At the same depth of tailings pond, when Cu2+ migrated for 365 days, the permeability coefficient increased with the increase of pollutant Cu2+ concentration. The concentration of heavy metal increased with the increase of migration time.

Detection of Melt Ponds on Arctic Summer Sea Ice From ICESat‐2

AbstractHemisphere‐wide observations of melt ponds on sea ice are needed to understand their influence on the surface radiation budget of the Arctic Ocean and to extend the satellite sea ice thickness data record. Here we present a first assessment of NASA's Ice, Cloud, and land Elevation Satellite‐2 (ICESat‐2) over individual Arctic sea ice melt ponds with different reflective properties. We use coincident high‐resolution satellite imagery from WorldView‐2 and Sentinel‐2 over different sea ice topographies to show that smooth ponds are highly reflective and can saturate the ICESat‐2 photon detection system. Rougher ponds have a more varied backscatter signal, and in some cases both the water and underlying ice surfaces are visible in photon height distributions. Characterizing the complex photon backscatter signals of melt ponds on sea ice is a first step toward automating retrievals of pond parameters such as width, melt pond fraction and depth, and improving higher‐level ICESat‐2 sea ice height and freeboard products.

Field Design for Enhancing Water Productivity in Waterlogged Areas with Efficient Water Harvesting and Farming System

Low productivity in waterlogged ecosystem is due to excess and deficit water stress during wet season and dry season, respectively. Good quality surface water abundantly available in the ecosystem can be harvested and used efficiently in farming system for enhancing land and water productivity. For deep waterlogged areas (ponding depth > 1 m), improved rice–fish integrated farming system is suggested. Land modifications for this include excavating soil from a pond refuge (7% area) and two side trenches (10% area), and constructing wide dykes (23% area) on four sides of the system. Water harvesting up to potential level and growing of water loving crops (water chestnut, deep water rice) is suggested. Emphasis is given to grow dry season rice with irrigation requirement of 572.4 mm (dry season rainfall not considered) for the test soil with low seepage percolation loss (0.47 to 1.93 mm day−1 during November to April). This was due to high clay content (52 to 55%) having wet swelling property. Dry season rice occupying 6000 m2 area in 1 ha rice–fish system area may demand 3434 m3 additional water considering residual harvested water (200 mm). A supporting farm pond (45 m × 40 m × 3 m) located nearby may provide this demand including pisciculture and dyke crops. For moderately deep water logged area (ponding depth 0.5 to 1 m), adoption of wide spaced creeper crop, drip irrigation and early seedling raising are suggested for water saving in dry season. Water requirement for 1 ha dry season pumpkin crop is 4200 m3. Supporting farm pond (45 m × 40 m × 3 m) is required for meeting the irrigation demand of pumpkin, dyke crops and pisciculture in farm pond.