Agricultural Drainage Systems Research Articles

Workshop Pemahaman Gen Z tentang Banjir dan Pencegahan

Flooding is an event that occurs as a result of the accumulation of water and cannot be accommodated by the soil.Flooding in Jakarta has become a routine problem over time, due to natural and human factors faced by the DKI Jakarta community.Losses caused by floods, especially indirect losses Not only the physical impacts suffered by the community but also non-physical losses such as schools being demolished, prices of basic necessities rising, and sometimes even deaths. Kodoatie and Syarief (2006) provide some examples of flood impacts or losses, loss of life or injury, property loss, settlement damage, trade area damage, industrial area loss, agricultural land damage, drainage and irrigation system damage, road and railway damage, highways, bridges, and airports damage, telecommunications system damage. Then the DKI Jakarta Regional Government coordinates with the Central Government to address the problem, the flood management policies are divided into short, medium and long-term periods. (Handayani, 2013). In this service to the community, there is an understanding of flooding and persecution using the method of devotion to the society in the form of socialization. This activity was followed by 24 people of the Generation Z, this Socialization has the theme “Flood Prevention and Management”. The purpose of this socialization is to expect the generation Z to gain a better understanding of the Flood and to emphasize the sense of self-awareness not to take actions that aggravate the flood.

Land drainage functioning and hydrological impacts in rural catchments: model development and field experiments

The development of an integrated theory of subsurface drainage based on hydrology and hydrogeology concepts is presented. The historical context, the main hypothesis derived from the Boussinesq equation and the validation of the model predictions are discussed. Theoretical developments of this equation demonstrate that a single parameter (σ)—a combination of soil and drainage system properties—is sufficient for predicting the dynamics of subsurface drain flow rates. We also demonstrate that these drain flow rates are a function of the level of water replenishment in the system (classically the water table elevation), of the recharge intensity of the aquifer and of a buffer function related to the swelling or deflation of the water table shape during recharge events. For values of σ>1, the buffer role of the water table is negligible. In that case approx. 13% of the water table recharge contributes to the flow rate, which is shown to explain the observed disconnection between water table elevations and peak flow rates at the outlet of classic agricultural drainage systems and to predict these peak flow rates accurately. A modelling approach based on this theory and validated experimentally (SIDRA model) allowed us to test the quality of the peak flow prediction. The SIDRA model also includes a surface runoff module and has been coupled to different modelling tools and used to analyse the impacts of subsurface drainage on water quality. The approach contributed towards the development of tools that helped to connect better the drainage systems to the hydrological functioning of watersheds.

Flow Rate and Volume Estimates from Variable Frequency Drive Operated Drainage Sump Pumps

Highlights This article provides an overview of operations and benefits of using a variable frequency drive to operate agricultural subsurface drainage system sump pumps. A methodology is proposed to monitor flow rates leaving agricultural subsurface drainage pump stations via a MATLAB algorithm. The results of this research were mixed because the algorithm estimates did not always match with the corresponding flowmeter measurements. Abstract. Subsurface drainage plays a crucial role in excess water removal through perforated pipes buried in the soil. The Red River Valley of eastern North Dakota and west central Minnesota often requires pumped drainage outlets due to its flat topography, with many modern systems incorporating variable frequency drives (VFD) for improved efficiency. VFDs adjust pump speeds to match drainage needs, but this dynamic operation complicates accurate flow rate estimation for edge-of-field monitoring. This project aimed to devise an automated method for calculating flow rate estimates from VFD pumping systems involving tank geometry, operational water levels, and pump duty cycling. Linear regressions with calibration data from a transit-time ultrasonic flowmeter produced mixed outcomes. Some linear regressions revealed errors in calculated versus measured flow rate of =14%, while other regressions showed errors nearing 40%. To address this, future efforts should explore methods incorporating the pump’s electrical characteristics. This approach would provide a more accurate representation of the unstable and intricate pumping operations during transient conditions. Keywords: Edge-of-field monitoring, Flow rate, Pump, Red River Basin, Subsurface drainage, Variable frequency drive

Evaluation of drainage water quality for irrigation reuse in Kulfo and Hare irrigation command areas, southern Ethiopia

Abstract Water from agricultural drainage systems can be reused when its quality is good or blended with irrigation canal water to overcome the water shortage. The primary goal of this research was to determine the quality of surface drainage water in the Kulifo and Hare irrigation projects for irrigation reuse. Water quality was evaluated in situ and in the laboratory during the irrigation season of 2022. Turbidity, TDS, pH, EC, and DO were analyzed in the field using an Aqua meter. Fifty-seven water samples were collected and analyzed for the major cation (Na+, Ca2+, K+, and Mg2+) and anion (HCO3−, CO32−, Cl−, and SO42−). The result of the drainage water quality index study, according to the water quality index for irrigation purpose reuse, ranged from 47.84 to 84.89. This indicated that the suitability of drainage water reuse for irrigation purposes was categorized as ‘poor to very poor,’ except in Shara community-managed farms. Therefore, to avoid the impact on soil quality for crop production due to the hazard of poor agricultural drainage water for irrigation reuse in the study area, it needs to be treated before being reused for irrigation purposes, except at the Shara irrigation community-managed farm.

Dissolved organic matter distribution in the water column and sediment pore water in a highly anthropized coastal lagoon (Mar Menor, Spain): Characteristics, sources, and benthic fluxes

Coastal lagoons are among the most productive and biodiverse systems in the world and are important sentinels of climate change. The Mar Menor is one of the largest coastal lagoons in the Mediterranean, providing a variety of ecosystem services and resources to the community. However, in recent decades this lagoon has suffered drastic changes and degradation caused by human activities. We analyzed the concentration of dissolved organic carbon (DOC) and the optical properties of dissolved organic matter (DOM) in the water column and sediment pore water during the summer and winter of 2018 and during eighteen months from 2016 to 2018. Overall, we found that the composition of DOM is mainly related to and enhanced by anthropogenic activities and microbial metabolism. DOM enters the lagoon via urban and agricultural runoff, drainage systems, and wastewater treatment plants. Additionally, strong microbial metabolism in sediments leads to differences in DOM composition between water and sediments. In the water column, humic-like components accounted for 71 % of the total DOM, while protein-like compounds were most abundant in sediment pore water. We observed a strong seasonal variability associated with precipitation and the system collapse in 2016 (phytoplankton bloom), which resulted in the death of 80 % of macrophytes. The sediments act as a source of DOM to the overlying water, likely due to relatively high organic matter content and intense microbial activity, primarily through anaerobic pathways. Benthic fluxes of DOC ranged from 5.24 to 33.30 mmol m−2 d−1, being higher in winter than summer 2018 and decreasing from north to south, likely related to lower residence time in the northern basin, groundwater discharge and accumulation of organic matter from the dead meadows. We estimate a net flux of DOC from the Mar Menor toward the Mediterranean Sea of 1.57 × 107 mol yr−1.

Creation of a cooperative for the joint operation of agricultural machinery: the need, prospects, the mechanism of intra-economic relations

Among many factors of sustainability of agricultural production, a special place is given to the cooperation of agricultural enterprises. The goal is to substantiate the need and prospects for the creation of cooperatives for the joint use of agricultural machinery, irrigation and drainage systems, the development of principles for regulating intra-economic relations between their members in the south of the republic, and the determination of the prerequisites for the development of cooperative structures. Methods – monographic, calculation-constructive, analytical, economic-statistical, social survey of agricultural producers who participated in the training seminars PMID-2. Results – analysis of the status of pilot projects of agricultural cooperatives of the Maktaaral and Shardara districts of the Turkestan region was carried out, on the basis of which promising directions for their improvement, organizational and economic conditions for the creation of a cooperative machine-technological station (MTS) were identified in order to organize the collective operation of agricultural machinery; building economic ties between members and the cooperative association; The demand for expanding the scope of the model of cooperation for the collective use by agricultural producers of irrigation and drainage mechanisms for irrigated areas in compliance with the hydraulic principle is shown, which will help increase land fertility, crop yields, and, accordingly, the efficient use of land, water and other resources. Conclusions – the results of the study on the implementation of the PMID-2 project, measures to provide cooperating entities with agricultural machines as part of the implementation of the Pilot Project of the Zhambyl region and scaling it in other regions of Kazakhstan confirm the expediency of continuing the process of cooperating small farms, improving the material and technical base of agricultural producers, providing measures of state support for the purchase of equipment through concessional lending and rational use, as well as irrigation and drainage systems by employees of an agricultural cooperative.

The impact of extensive agricultural water drainage on the hydrology of the Kleine Nete watershed, Belgium

Agricultural water drainage can significantly lower groundwater levels and affect catchment hydrology. Therefore, building models with and without these features can indicate an adverse impact on the geohydrological process. Therefore, the standalone Soil Water Assessment Tool (SWAT+) model was initially developed to simulate streamflow at the Kleine Nete catchment outlet. Next, a physically based and spatially distributed groundwater module (gwflow) was integrated into the SWAT+ model and calibrated for stream discharge at the catchment outlet. Finally, the same model was calibrated for both streamflow and groundwater heads. These final model parameters are used to investigate the basin-wide hydrologic fluxes with and without including agricultural drainage systems in the model scheme.The result suggested that the standalone SWAT+ model poorly represented the stream discharge and attained low NSE values of 0.18 and 0.37 during the calibration and validation periods, respectively. Integrating the gwflow module to SWAT+ improved the model representation of stream discharge (NSE = 0.91 and 0.65 for calibration and validation periods, respectively) and groundwater heads. However, calibrating the model for only streamflow resulted in a high root mean square error (above 1 m) for groundwater head, and the seasonality is not captured. On the other hand, calibrating the coupled model for streamflow and hydraulic head reduced the root mean square error (below 0.5 m) and captured the seasonality of groundwater level fluctuations. Finally, drainage application resulted in a 50 % (from 33.04 mm to 16.59 mm) reduction in groundwater saturation excess flow and an 18.4 mm increment in drainage water to streams. To conclude, the new SWAT+gwflow model is more appropriate than the standalone SWAT+ model for the case study. Furthermore, calibrating the SWAT+gwflow model for streamflow and groundwater head has improved the model simulation, with implications for general coupled models where representing surface and groundwater in the calibration strategy is beneficial.

Environmental factors influencing DDT–DDE spatial distribution in an agricultural drainage system determined by using machine learning techniques

The presence and persistence of pesticides in the environment are environmental problems of great concern due to the health implications for humans and wildlife. The persistence of DDT–DDE in a Mediterranean coastal plain where pesticides were widely used and were banned decades ago is the aim of this study. Different sources of analytical information from water and soil analysis and topography and geographical variables were combined with the purpose of analyzing which environmental factors are more likely to condition the spatial distribution of DDT–DDE in the drainage watercourses of the area. An approach combining machine learning techniques, such as Random Forest and Mutual Information (MI), for classifying DDT–DDE concentration levels based on other environmental predictive variables was applied. In addition, classification procedure was iteratively performed with different training/validation partitions in order to extract the most informative parameters denoted by the highest MI scores and larger accuracy assessment metrics. Distance to drain canals, soil electrical conductivity, and soil sand texture fraction were the most informative environmental variables for predicting DDT–DDE water concentration clusters.

A Sustainable Approach for Removing Organic Pollutants from Food Processing Effluents Using Unmodified Cocopeat as an Adsorbent

Food production (chips) uses raw materials such as tapioca, cassava, banana, and many more, which contribute to excessive pollutants in the water. Thus, there is a need to treat effluent sufficiently to prevent undesired pollutants from being released into the receiving water bodies, such as rivers and agricultural drainage systems. This study aims to investigate the effectiveness of cocopeat in removing targeted parameters such as suspended solids (SS), chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), and total phosphorus (TP) from the chips processing effluent. Batch experiments were conducted to determine optimum operating parameters, including the adsorbent dosage, contact time, and shaking speed. This was done to identify the best removal rates of SS, COD, NH3-N and TP from effluent food processing samples taken from two different discharge points based on their usages. The experimental results show that at the optimum conditions of pH 7, cocopeat dosages of 800 mg/L, contact time of 30 minutes, and shaking speeds of 200 rpm, the unmodified cocopeat achieved 17.3% and 19.8% of SS removal, 35.5% and 28.9% of COD removal, 40.7% and 30.5% of NH3-N removal, and 53.5% and 59.2% of TP removal, from Point A and Point B effluent, respectively. Besides, the maximum adsorption capacity achieved by unmodified cocopeat towards SS (1.5-14.0 mg/g), COD (16.88-17.75 mg/g), NH3-N (0.31-0.32 mg/g) and TP (1.46-1.50 mg/g) are comparable to the adsorption capacities reported by previous researchers. This finding suggests that cocopeat could potentially replace the commercially developed adsorbents for the treatment. Furthermore, this study gave insights into the feasibility of sustainable treatment using cocopeat as an adsorbent for medium-strength effluent. However, it is suggested that further alteration of the cocopeat characteristics, either by chemical or physical modifications, and its sludge disposal methodcould be explored further to enhance the treatment performance.

Experimentally Based Numerical Simulation of the Influence of the Agricultural Subsurface Drainage Pipe Geometric Structure on Drainage Flow

The geometric structure of corrugated plastic pipes affects performance in agricultural subsurface drainage systems. To explore the influence of pipe geometry on flow field characteristics and the characterization of water movements, we developed a three-dimensional (3D) steady-state subsurface drainage model based on computational fluid dynamics (CFD). An analysis of the CFD and sand tank results indicated that the proposed model can accurately simulate the subsurface drainage process (R2 = 0.99). The corrugation structure parameters of the drainpipe, including the outside diameter, corrugation valley width and corrugation height, were taken as the objects for this study, and the influence of corrugation parameters on drainage discharge was orthogonally analysed. During drainage, the soil water initially collects in the corrugation valley and then approximately ninety percent of the water flows into the pipe through the bottom perforations; increasing the contact face area between the corrugation valley and soil can increase the flow rate of the drainpipe and the water table height above the pipe, which decreases the intersection position of the pipe and water table. The results of the analysis of the range and variance of the orthogonal experiment showed that the order of the primary and secondary factors influencing the drainage discharge was the outside diameter, corrugation valley width and corrugation height, with the outside diameter being most critical influencing factor.

Water quality and interaction between groundwater and surface water impacted by agricultural activities in an oasis-desert region

A comprehensive understanding of groundwater dynamics and its interaction with surface water under the influence of agricultural activities is essential for local agriculture, ecology and resident in arid regions, which is poorly understood in arid oasis-desert region. In our study, with emphasis on a comparison of hydrogeochemical characteristics between the oasis (irrigated) and desert (non-irrigated) areas, the water quality and groundwater-surface water interaction of a typical oasis-desert system with a rapid irrigation agriculture development were examined to clarify the effects of agricultural activities on groundwater level and quality using stable isotopic and hydrochemical data of 83 water samples. Results showed that cultivated land area increased by 121.8 % (732.4 km2) during 2000 to 2020, mainly transferring from grassland and bare land. Groundwater EC ranged from 786 to 49,400 μS/cm, with weakly alkaline. Shallow groundwater had a much higher EC than other water components. Stable isotopic and EC values of shallow groundwater in the non-irrigation areas were much greater than those in the irrigation areas, whereas middle groundwater isotopic values were more depleted in the desert than in the oasis. Shallow groundwater EC value was lower in summer, middle groundwater had higher EC in summer. Streamflow and confined water in the study area are suitable for agricultural irrigation, but phreatic water in the oasis is generally not suitable for irrigation at present. The groundwater chemistry was mainly controlled by strong evaporation, dilution, mixing, water-rock interaction and agricultural drainage. Groundwater in the irrigation areas was recharged by ephemeral runoff seepage, irrigation return flow and subsurface lateral inflow. Long-term development of irrigation agriculture (large-scale land reclamation, irrigation and groundwater pumping) in arid region has caused groundwater level decline and salinization, with a strong interaction between phreatic water and surface water. Hence, decreasing irrigation area and groundwater exploitation, carrying out gradual ecological restoration, improving water-saving efficiency and agricultural drainage system would be the viable method to restore groundwater and maintain the oasis-desert ecosystem coexistence in arid regions in the context of climate change.

Study on the Hydraulic and Energy Loss Characteristics of the Agricultural Pumping Station Caused by Hydraulic Structures

The pumping station is an important part of the agricultural irrigation and drainage system. The sump is one of the common water inlet types of agricultural pumping stations. In the sump, to facilitate the installation and maintenance of equipment, some hydraulic structures, such as pump beams, maintenance platforms and chest walls, are added to the sump. At present, the impact of hydraulic structures in the sump on the hydraulic performance of the pump device is not clear, so this paper focused on the impact of hydraulic structures on the hydraulic characteristics and entropy generation characteristics of the pump device by using numerical simulation methods. The results showed that the installation of hydraulic structures in the sump has the greatest impact on the efficiency of the pump device. The efficiency coefficient increased after adding a pump beam in the sump and decreased by about 2% after adding a maintenance platform and a water retaining chest wall. Results also showed that the installation of hydraulic structures in the sump will lead to uneven distribution of entropy generation in the sump, especially in the vicinity of the hydraulic structures. The installation of the maintenance platform and chest wall will lead to the increase of the total entropy generation in the sump, which also means that the hydraulic loss in the sump will increase accordingly. Hence, in addition to the pump beam, other structures should be avoided in the sump.

Extreme rainfall analysis for an agricultural land drainage system

ABSTRACT The present study highlights the IS 8835:1978 recommendation for the planning and design of surface agricultural drains adopted uniformly across India. The current analysis aimed to compute the agricultural land drainage design and cross-drainage structure for 5-year and 50-year frequencies, respectively, using 3-day rainfall for the areas belonging to three different agro-climatological zones (including four districts, i.e. Surat, Ahmedabad, Jaipur and Mumbai). Extreme rainfall analysis using 3-day fixed window (FW) and sliding window (SW) rainfall was carried out using the probabilistic approach and the maximum rainfall depth-duration-frequency curves. For the 5-year (50-year) frequency, the 3-day FW rainfall for Surat, Ahmedabad, Jaipur, and Mumbai was 303 mm (490 mm), 235 mm (442 mm), 147 mm (326 mm), and 417 mm (667 mm), respectively, whereas the 3-day SW rainfall is 345 mm (583 mm), 258 mm (473 mm), 168 mm (359 mm), and 485 mm (765 mm), respectively. The trend analysis results showed the non-monotonous increasing (decreasing) trend over study regions. The SW rainfall was higher than the corresponding FW values. The results presented in this study can be adopted in the design of the agricultural land drainage network and cross-drainage structure in the regions under consideration.

Farm management optimization under uncertainty with impacts on water quality and economic risk

Farm management decisions under uncertainty are important, not only for farmers trying to maximize their net income, but also for policy makers responsible for incentives and regulations to achieve environmental goals. We focus on corn production as a significant contributor to the economy of the US Midwest. Nitrogen is one of the key nutrients needed to increase production efficiency, but its leaching and loss as nitrate through subsurface flow and agricultural drainage systems poses a threat to water quality. We build a novel two-stage stochastic mixed-integer program to find the annual farm management decisions that maximize the expected farm profit. A decomposition-based solution strategy is suggested to reduce the computational complexity resulting from the predominance of binary variables and complicated constraints. Case study results indicate that farmers may compensate for the additional risks associated with nutrient reduction strategies by increasing the planned nitrogen application rate. Significant financial incentives would be required for farmers to achieve substantial reductions in nitrate loss by fertilizer management alone. The complicated interactions between fertilizer management and crop insurance decisions observed in the numerical study suggest that crop insurance programs can affect water quality by influencing the adoption of environmentally beneficial practices.

Pesticide concentrations in agricultural storm drainage inlets of a small Swiss catchment

Agricultural pesticides transported to surface waters pose a major risk for aquatic ecosystems. Modelling studies indicate that the inlets of agricultural storm drainage systems can considerably increase the connectivity of surface runoff and pesticides to surface waters. These model results have however not yet been validated with field measurements. In this study, we measured discharge and concentrations of 51 pesticides in four out of 158 storm drainage inlets of a small Swiss agricultural catchment (2.8 km2) and in the receiving stream. For this, we performed an event-triggered sampling during 19 rain events and collected plot-specific pesticide application data. Our results show that agricultural storm drainage inlets strongly influence surface runoff and pesticide transport in the study catchment. The concentrations of single pesticides in inlets amounted up to 62 µg/L. During some rain events, transport through single inlets caused more than 10% of the stream load of certain pesticides. An extrapolation to the entire catchment suggests that during selected events on average 30 to 70% of the load in the stream was transported through inlets. Pesticide applications on fields with surface runoff or spray drift potential to inlets led to increased concentrations in the corresponding inlets. Overall, this study corroborates the relevance of such inlets for pesticide transport by establishing a connectivity between fields and surface waters, and by their potential to deliver substantial pesticide loads to surface waters.

Acid sulfate soils and their impact on surface water quality on the Swedish west coast

Study regionHalland county, located on the Swedish west coast, with a special focus on the area around Ramsjö canal (Falkenberg municipality). Study focusThis study contributes to the understanding of the development of active acid sulfate soils and environmental consequences of leaching from these soils in an area without previous investigations. Samples taken from different soil profiles in an agricultural area and water samples from the agricultural drainage system were analysed in pH, electrical conductivity, and metal concentrations. To evaluate the on-site situation, the results of the soils sample analysis were compared to the national soil classification system and the water samples to areas in northern Europe affected by acid sulfate soils. New hydrological insights for the regionThe results prove the existence of active acid sulfate soils in a coastal area in Halland. In the study region, acid sulfate soils were discovered in an agricultural area of drained wetland and peatland. Water samples taken from the drainage system and a man-made canal flowing into Kattegat Sea have low pH combined with high electrical conductivity and increased metal concentrations. This is a direct consequence of intensive leaching from the discovered acid sulfate soils in that area. Therefore, this is the first case study proving the existence of acid sulfate soils and highlighting their environmental impact on surface water quality on the Swedish west coast (i.e. outside the Baltic Sea Basin).

Bioaugmentation potential of a cold-adapted and nitrate-reducing fungus to enhance nitrate removal in woodchip bioreactors

Woodchip bioreactors are a promising approach to remove nitrate from agricultural drainage systems; however, their low removal efficiency at cold temperatures remains a significant challenge. Here we analyzed the efficacy of fungal inoculation to enhance nitrate removal in woodchip bioreactor microcosms under cold conditions. Among the cold-adapted, nitrate-reducing, and cellulose-degrading fungi previously isolated from soil, we identified Linnemannia hyaline strain SCG-10 as the fastest nitrate reducer. Inoculation of this fungal strain enhanced the rates of nitrate reduction, N2 production, and dissolved organic carbon production in woodchip bioreactor microcosms at 5 °C. Production of N2O was minor (<1%) in this study most likely due to the enhanced activity of N2O reducers by labile carbon. Quantitative PCR for nitrogen cycle-related genes showed the active transcription of both fungal and bacterial denitrification genes. These results suggest that inoculating cold-adapted, nitrate-reducing, and cellulose-degrading fungi is a promising approach to remove nitrate from agricultural fields under cold conditions.

Impaired cellulose decomposition in a headwater stream receiving subsurface agricultural drainage.

BackgroundAgricultural development of former wetlands has resulted in many headwater streams being sourced by subsurface agricultural drainage systems. Subsurface drainage inputs can significantly influence stream environmental conditions, such as temperature, hydrology, and water chemistry, that drive ecological function. However, ecological assessments of subsurface drainage impacts are rare. We assessed the impact of an agricultural drainage system on cellulose decomposition and benthic respiration using a paired stream study in a headwater branch of Nissouri Creek, in Ontario, Canada. Adjacent first order segments sourced by a spring-fed marsh and a cropped field with subsurface drainage, as well as the adjoining trunk segment, were sampled over a year using the cotton strip assay to measure cellulose decomposition and benthic respiration.ResultsAssessments of cellulose decomposition revealed a one-third reduction in the drainage-sourced segment compared to marsh-sourced segment. Between segment differences in cellulose decomposition were associated with reduced summer temperatures in the drainage-sourced segment. Impacts of stream cooling from the drainage-sourced segment were transmitted downstream as cellulose decomposition was slower than expected throughout the drainage-sourced segment and for several hundred meters down the adjoining trunk segment. Benthic respiration only differed between the drainage- and marsh-sourced segments in spring, when stream temperatures were similar.ConclusionsOur findings suggest there may be a widespread reduction in cellulose decomposition in streams across similar agricultural regions where subsurface drainage is prevalent. However, cooling of streams receiving significant amounts of water inputs from subsurface drainage systems may impart increased resiliency to future climate warming.

Occurrence of Pesticides Associated with an Agricultural Drainage System in a Mediterranean Environment

Surface water pollution (as a result of pesticides) is a major problem, due to the negative impact on human health and ecosystems. The excessive use and persistence of surface water pollution in the environment may present a notable risk. In this article, DDT and its metabolite DDE hereafter, DDT–DDE), and a commonly used pesticide (herbicide) glyphosate, were analyzed in agricultural drainage waters; afterward, a spatial analysis was applied to identify potential areas of high pesticide occurrence in an agricultural Mediterranean coastal floodplain. The spatial distribution of banned (Directive 79/117/EEC), yet highly persistent pesticides in the environment, such as DDT (and metabolites), was compared with the (currently and mostly used) glyphosate. A sequence of various point patterns, spatial analysis methods, and non-parametric statistics, were computed to elucidate the pesticide pollution hotspots. As a reference value, almost 70% of the water samples were above the World Health Organization (WHO) guideline for DDT (and metabolites) for drinking water (1 µg/L), with a maximum of 6.53 µg/L. Our spatial analysis approach revealed a significantly high concentration of DDT–DDE clusters close to wetlands in natural parks, where mosquitos are abundant, and pesticides persist and flow to the surface waters from soil and groundwater pools. Conversely, glyphosate concentrations were below WHO guidelines; their spatial patterns were related more toward current agricultural uses in the southern sector of the study area.

Dilemmas of public goods provisioning: institutional mechanisms for agricultural drainage management in Ohio, USA

Institutions are critical for collective action around several environmental policy issues. A seldom-studied issue, agricultural drainage, provides a rich setting to examine how institutional mechanisms interact with two variables linked to collective action: group size and heterogeneity. In this study, we examine institutions for establishing and maintaining agricultural drainage systems in the Western Lake Erie Basin region of Ohio. Specifically, we examine whether and how drainage management institutions interact with two variables, group size and heterogeneity in benefits and costs, for solving the public-good dilemmas of agricultural drainage. Data for this study come from a comparative case study design, using semi-structured in-depth interviews, and a landowner survey. Results suggest that the Olson effect for group size is mediated by institution type, and heterogeneity in benefits and costs is mediated by fairness perceptions, in affecting incentives for collective action. We discuss our findings in light of theories of collective action.