Rapid Assessment Of Water Quality Research Articles

Towards Autonomous, Optimal Water Sampling with Aerial and Surface Vehicles for Rapid Water Quality Assessment

Highlights A practical workflow for optimizing sampling tours for a team of surface and aerial vehicles was developed. Proposed workflow considers unique sensing capabilities of surface vehicles when assigning sampling locations. Likely optimal tours can be found in less than 30 s for practical water quality sampling requirements. Abstract. Most current marine aquaculture operations are located in coastal estuarine areas within one mile of the shoreline, and water quality in these production areas can quickly become unfavorable due to hydrodynamic processes and excessive runoff. The deployment of autonomous, robotic systems can improve the speed and spatiotemporal resolution of water sampling and sensing in mariculture production areas to assess water quality in the context of food safety. Specifically, teams of both aerial and surface vehicles can be deployed simultaneously to capitalize on the benefits of each system; however, a method to optimally design a feasible sampling tour for each robot is needed to maximize sample capacity and ensure efficient water sampling missions. This research brief presents the problem formulation and a solution method to determine optimal tours for a team of aquatic surface and aerial vehicles while considering different vehicle sampling capacities and endurance constraints. This method was implemented to design sampling missions of 15, 20, and 30 samples in both a 0.25 km2 and 3.9 km2 site, using sampling capacity and endurance constraints corresponding to real-world robots used for water sampling in mariculture environments. Results indicate that this optimization problem can be solved in near-real time in the field and yields feasible sampling tours for surface and aerial vehicles under different constraints. This work is a practical step towards developing teams of collaborative robots to persistently monitor adverse mariculture growing conditions so producers can implement data-driven, timely management strategies. Keywords: Mariculture, Robotics, Traveling salesperson problem, Vehicle routing.

AQUATIC INVERTEBRATES ASSEMBLAGES RESPONSES TO WATERSHED LAND USE IN TABIN WILDLIFE RESERVE (TWR), LAHAD DATU, SABAH, MALAYSIA

A study on the aquatic invertebrate communities was conducted at Tabin Wildlife Reserve (TWR), Lahad Datu, Sabah, with the objectives to study (i) the diversity of aquatic invertebrates across different land use, (ii) the composition of aquatic invertebrates in different habitats and microhabitats in the stream, and (iii) the relationship between invertebrates and the water quality of the stream. Sampling was done at Sg. Lipad which flows across the secondary forest area and plantation area. Kick net method was used to sample the aquatic invertebrates for 14 continuous days in January to February 2015. A total of 3,579 individuals were sampled consisting of 76 families from eight orders, in both of the land uses. The diversity of aquatic invertebrates in the secondary forest was found to be slightly higher than plantation area with H’= 3.213 and H’= 3.188 respectively. The aquatic invertebrates were also found to be more abundant in riffle habitat, and the least in pool habitats. The diversity for pool habitat, however, was the highest among all other habitats with H’= 3.709. Both physico-chemical parameters and biotic indices indicated that the invertebrate communities were affected by the water quality in the surroundings, and may be used for rapid assessment of water quality at TWR.

Diversity of the Summer Phytoplankton of 43 Waterbodies in Bulgaria and Its Potential for Water Quality Assessment

The general awareness of the threats on biodiversity and water quality raised the number of studies that use phytoplankton in assessment procedures. Since most metrics require obtaining mean values, this paper presents data that may help speed up field work and find indicators for a rapid water quality assessment based on single samplings, allowing simultaneous work on many sites. The phytoplankton from 43 Bulgarian waterbodies collected during three summer campaigns (2018, 2019, 2021) at sites selected after drone observations was studied by conventional light microscopy (LM) and an HPLC analysis of marker pigments. Our results allowed us to recommend drones and the HPLC application as reliable methods in rapid water quality assessments. In total, 787 algae from seven phyla (53 alien, new for Bulgaria) were identified. Chlorophyta was the taxonomically richest group, but Cyanoprokaryota dominated the biomass in most sites. New PCR data obtained on anatoxin and microcystin producers confirmed the genetic diversity of Cuspidothrix and Microcystis and provided three new species for the country’s toxic species, first identified by LM. A statistical analysis revealed significant correlations of certain algal phyla and classes with different environmental variables, and their species are considered promising for future search of bioindicators. This is especially valid for the class Eustigmatophyceae, which, as of yet, has been almost neglected in water assessment procedures and indices.

Evaluation of Water Quality by Benthic Macroinvertebrate at the Jukjeon Stream in Korea

This work was studied to investigate the water quality of the Jukjeon stream in Korea based on benthic macroinvertebrates. Several ecological score of benthic macroinvertebrate community were used in the estimation of stream from each of the three stations of the sub-watersheds. During the study periods, the results showed a total of 619 individual benthic macroinvertebrates were collected, including 23 families and 44 species. The first dominant species was Culicini sp. and second was Baetis fuscatus. Ecological score of benthic macroinvertebrate community (ESB) was varied from 61 (St. D) to 71 (St. A) with a mean of 66.5. Water quality at the Jukjeon Stream was grade I. The values of benthic macroinvertebrate index (BMI) at St. A and St. B were 60.4 and 53.4, respectively. Water quality at the two stations was grade C (moderate) on the based BMI. The values of BMI at St. C and St. D were 45.5 and 39.6, respectively. Water quality at the two stations was grade D (bad). The Shannon diversity index (H') of diversity was varied from 3.76 (St. A) to 4.18 (St. B) with a mean of 4.05. The rank percentages of species based on individual abundance (RI) were 4.84 (St. A), 5.66 (St. B), 6.31 (St. C), and 5.97 (St. D). Evenness indices (J) were varied from 0.79 (St. C) to 0.84 (St. B). The values of EPT (Ephemeroptera, Plecoptera and Tricoptera) at St. A, St. B, St. C, and St. D were 0.56, 0.48, 0.29, and 0.17 with a mean of 0.37, respectively. The EPT group accounted for 37% of the total species and 53% of the total individuals. The diversity and richness indices were lower in St. A than in the other stations. In this study, rapid assessment of water quality by macroinvertebrate indicators involves effort and reduced cost in natural stream evaluation.

A soft sensor for simulating algal cell density based on dynamic response to environmental changes in a eutrophic shallow lake

There is a great need for timely monitoring and rapid water quality assessment to control the algal blooms that often occur in eutrophic lakes. While algal cell density (ACD) is a critical indicator of algal growth, field monitoring is laborious and time-consuming, and rapid assessment of algal blooms based on ACD is often not possible. To address the limitations of conventional ACD detection, we proposed a soft sensor approach that uses surrogate indicators to simulate ACD in machine learning models. We conducted a case study using monitoring data from Chaohu Lake collected between 2016 and 2019. We found that ensemble learning models, especially extreme gradient boosting (XGBoost), outperformed traditional machine learning algorithms by comparing various machine learning algorithms. Also, considering the influence of input variable selection on model performance, we combined the results of different filter methods in the multi-stage variable selection process. Finally, we screened out seven key variables out of the 43 initial candidate variables, including dissolved oxygen (DO), chlorophyll-a (Chl-a), Secchi disk depth (SD), pH, permanganate index (CODMn), week of the year (WOY), and wind velocity (WV). Their inclusion substantially improved data accessibility and supported the development of a rapid simulation model. The final model was capable of reliable spatiotemporal generalization, with an overall R2 value of 0.761. On the theoretical side, our study makes a new attempt to simulate ACD values in a eutrophic lake. For practical purposes, the soft sensor can facilitate the rapid assessment of bloom conditions, which helps the local administration with emergency prevention and control.

Rapid Water Quality Assessment as a Quick Response of Oil Spill Incident in Coastal Area of Karawang, Indonesia

The purpose of this study was to assess the effect of oil spills on seawater quality along the coastal waters of Karawang Regency. Several laboratories were involved in measuring water quality to get representativeness of the location of the exposed waters both spatially and temporally. The measurement of seawater quality was carried out in situ and in the laboratory. Seawater quality data were compared with quality standards and discussed descriptively. All key water quality parameters (total petroleum hydrocarbon, polycyclic aromatic hydrocarbon, phenol, MBAS, and oil and grease) were below the detection limit of equipment, and a number of metals generally met quality standards. Only shortly after the oil spill in the vicinity of the spill source, the Ni metal exceeded the quality standard. However, after some time, spatially and temporally Ni has met the quality standard. Parameters not related to oil spills such as total phosphate generally did not meet quality standards. This might be related to the high activity on land, such as waste from domestic, industry, and agricultural activities entering coastal waters. Based on intertemporal data, the effect of an oil spill on water quality was temporary. This shows that the handling of the impact of the oil spill has shown good results and the quality of seawater remained quite good. Oil spills that float on the ocean surface were picked up, and those that washed ashore were cleaned up and collected.

Methods for Contaminated Water Biotesting

The response of living organisms to pollution is manifested in physiological, morphological and behavioural changes, which makes biomonitoring a very convenient and predictable method. Daphnia magna, in particular, is the best indicator in the ratio of the time spent and of course the accuracy of the readings. Increasing the information content of biotesting waters of surface sources of water supply and drinking water on mollusks Daphnia magna S. through the use of a test feature of heart rate. The test durations were 48 and 3 hours, respectively. The heart rate measurement results indicate a low level of toxicity (range, 26.2 to 35.4%). The results of the study suggest that the rapid assessment of water quality with the use of Daphnia should rely more on the heart rate measurement. This method proved to be highly effective in estimating the water samples from the Flathet Reservoir, yielding data 73.11% faster than the immobilisation test. The sensitivity level was also 28.33% higher.

Spatial Differentiation Analysis of Water Quality in Dianchi Lake Based on GF-5 NDVI Characteristic Optimization

Remote sensing monitoring of aquatic vegetation is critical to the water quality evaluation of plateau lakes. To obtain a clear understanding of the water environment status of Dianchi Lake, a GF-5 hyperspectral characteristics-based optimal NDVI approach was employed to quantify the aquatic vegetation cover and analyze water quality. By characteristic bands recognition, the optimal NDVI was obtained; the spatial distribution of aquatic plants and water quality in Dianchi Lake were then analyzed. Results showed the following: (1) For Caohai, the optimal NDVI value was calculated by B86 in the red band range and B151 in the near-infrared band range, which achieve the best spectral response. For Waihai, the respective bands were B86 in the red band range and B99 in the near-infrared band range. (2) We also found significant regional differences in aquatic plants distribution for the study area. Caohai was dominated by aquatic plants and high-quality water areas only occurred in the northern tip. While the situation for Waihai was much optimistic, areas with poor water quality were mainly found in the north and south parts. Water quality also showed a descending trend from the lakeside zone to the lake center. (3) By comparing to previous studies, we concluded that policy interventions and water protection measures carried out by the government during the past years are extremely effective. The optimal NDVI method provides a reliable evaluation and is potentially transferable to other plateau lake areas as a robust approach for the rapid assessment of water quality.

Improved chlorination and rapid water quality assessment in response to an outbreak of acute watery diarrhea in Somali Region, Ethiopia

Abstract The Somali Region of Ethiopia has been affected by drought for several years. Drought conditions have led to food and water scarcity and a humanitarian crisis in the region. In January 2017, an outbreak of acute watery diarrhea (AWD) was declared in the region. AWD prevention and control activities include strengthening water, sanitation, and hygiene (WASH) services. Access to safe drinking water is critical in preventing transmission of AWD and chlorine is an effective chemical to disinfect water supplies. The US Centers for Disease Control and Prevention collaborated with the WASH Cluster and the United Nations Children's Fund, Ethiopia, to provide technical assistance to the Somali Regional Water Bureau to improve chlorination of drinking water supplies and quickly assess water quality improvements in Jijiga town, Fafan Zone. Timely sharing of surveillance and case investigation data allowed for the identification of gaps within the water supply system in Jijiga and implementation of centralized and decentralized chlorination interventions and monitoring systems. Pilot use of a rapid assessment to determine residual chlorine levels at various points in the city helped improve chlorination intervention impact. This work illustrates that rapid community-level water quality improvements can be implemented and assessed quickly to improve interventions during outbreaks.

Fluorescence excitation emission matrices for rapid detection of polycyclic aromatic hydrocarbons and pesticides in surface waters

Rapid water quality assessment was evaluated using an automated fluorescence analysis system.

Aquatic Insects and Water Quality Study at Kimanis River, Crocker Range National Park, Sabah, Malaysia

A survey on the aquatic insect communities was conducted in Kimanis River, Ulu Kimanis, Crocker Range Park (CRP), Sabah with the objectives to study (i) the composition of stream insect communities, (ii) stream water quality and (iii) the relationships between aquatic insects and freshwater quality parameters in Kimanis River, Ulu Kimanis, CRP. The sampling was carried out using surber net in October 2015 and January 2016. A total of 1,801 individuals from nine orders of 28 families were collected from Kimanis River. Trichopterans fauna was found to be the prominent taxa in this study. Shannon-Wiener Index of upstream strata was recorded slightly higher than downstream strata with H’= 1.97 and H’= 1.85 respectively. Water integrity of Kimanis River could be considered as excellent with minimal pollution. Both water quality parameters and biotic indices indicated that the aquatic insect population was affected by the water quality in their surroundings. This proved the use of aquatic insect communities as bioindicator for rapid assessment of water quality in CRP.

Rapid Assessment of Water Quality in Teluk Lake by Using Macroinvertebrates (A Family Level Biotic Index)

In this study the water quality of Teluk Lake, Jambi Province by biological indices using macroobenthic during December 2017 to March 2018 were evaluated. Macro obenthic have been the most commonly indicator of running water quality to rapidly detect water quality changes. The methodology consisted on three stages: 1) macro invertebrates sampling and and sorting of the organisms in laboratory, 2) taxonomic identification of organisms and 3) determination and scoring with the Biological Monitoring Working Party -Average Score per Taxon (BMWP-ASPT) index. Result of water quality of Teluk Lake based on the diversity of macroinvertebrates was degraded with BMWP-ASPT index below 4. Based on the BMWP-ASPT score of the macroinvertebrates, both of sampling 1 and 2 were polluted with the category of medium and heavily polluted. In general, the decreasing of water quality of Teluk Lake was due to anthropogenic activities, so that the intolerant macro invertebrates could not survive in polluted waters while the tolerant ones can adapt well to the polluted aquatic environment.

Sensing an intense phytoplankton bloom in the western Taiwan Strait from radiometric measurements on a UAV

Rapid assessment of algal blooms in bays and estuaries has been difficult due to lack of timely shipboard measurements and lack of spatial resolution from current ocean color satellites. Airborne measurements may fill the gap, yet they are often hindered by the high cost and difficulty in deployment. Here we demonstrate the capacity of a low-cost, low-altitude unmanned aerial vehicle (UAV) in assessing an intense phytoplankton (Phaeocystis globosa) bloom (chlorophyll concentrations ranged from 7.3 to 45.6mg/m3) in Weitou Bay in the western Taiwan Strait. The UAV was equipped with a hyperspectral sensor to measure the water color with a footprint of 5m at every 30m distance along the flight track. A novel approach was developed to obtain remote sensing reflectance (Rrs) from the UAV at-sensor radiometric measurements. Compared with concurrent and co-located field measured Rrs (14 stations in total), the UAV-derived Rrs showed reasonable agreement with root mean square difference ranging 0.0028–0.0043sr−1 (relative difference ~20–32%) of such turbid waters for the six MODIS bands (412–667nm). The magnitude of the bloom was further evaluated from the UAV-derived Rrs. For the bloom waters, the estimated surface chlorophyll a concentration (Chl) ranged 6–98mg/m3, which is 3–50 times of the Chl under normal conditions. This effort demonstrates for the first time a successful retrieval of both water color (i.e., Rrs) and Chl in a nearshore environment from UAV hyperspectral measurements, which advocates the use of UAVs for rapid assessment of water quality, especially for nearshore or difficult-to-reach waters, due to its flexibility, low cost, high spatial resolution, and sound accuracy.

Water quality assessment in reservoirs: Comparative analysis of bioindication systems based on macrobenthos characteristics

Data on the Ruza and Mozhaisk reservoirs are used to analyze the applicability of different sampling methods and bioindication systems for rapid water quality assessment. The collected data were analyzed with the use of twelve biotic indices and their modifications. The mean water quality estimate in the coastal zones of both reservoirs varied from “moderate” to “good” and corresponded to α-mesosaprobic zone. The best performance in saprobity assessment was demonstrated by Pantle–Buck index modified by M.V. Chertoprud in the coastal zone and Balushkina index in soft soils in the central zones of the reservoirs. It is proposed to extend the number of indicator taxa in Pantle–Buck index modified by M.V. Chertoprud by incorporating taxa typical of soft soils, in particular, Chironomid larvae from Chironomus plumosus group. Recommendations are given for carrying out express-monitoring of the state of reservoirs.

Portable LED fluorescence instrumentation for the rapid assessment of potable water quality

Characterising the organic and microbial matrix of water are key issues in ensuring a safe potable water supply. Current techniques only confirm water quality retrospectively via laboratory analysis of discrete samples. Whilst such analysis is required for regulatory purposes, it would be highly beneficial to monitor water quality in-situ in real time, enabling rapid water quality assessment and facilitating proactive management of water supply systems.A novel LED-based instrument, detecting fluorescence peaks C and T (surrogates for organic and microbial matter, respectively), was constructed and performance assessed. Results from over 200 samples taken from source waters through to customer tap from three UK water companies are presented. Excellent correlation was observed between the new device and a research grade spectrophotometer (r2=0.98 and 0.77 for peak C and peak T respectively), demonstrating the potential of providing a low cost, portable alternative fluorimeter. The peak C/TOC correlation was very good (r2=0.75) at low TOC levels found in drinking water. However, correlations between peak T and regulatory measures of microbial matter (2day/3day heterotrophic plate counts (HPC), E. coli, and total coliforms) were poor, due to the specific nature of these regulatory measures and the general measure of peak T. A more promising correlation was obtained between peak T and total bacteria using flow cytometry. Assessment of the fluorescence of four individual bacteria isolated from drinking water was also considered and excellent correlations found with peak T (Sphingobium sp. (r2=0.83); Methylobacterium sp. (r2=1.0); Rhodococcus sp. (r2=0.86); Xenophilus sp. (r2=0.96)). It is notable that each of the bacteria studied exhibited different levels of fluorescence as a function of their number. The scope for LED based instrumentation for in-situ, real time assessment of the organic and microbial matrix of potable water is clearly demonstrated.

Development and Application of a Loop‐Mediated Isothermal Amplification (LAMP) Method for Rapid and Sensitive Detection of Enterococcus faecalis in Drinking Water

AbstractThe genus Enterococcus comprises opportunistic pathogens such as Enterococcus faecalis and E. faecium, and is used to assess water quality. E. faecalis has become prominent in recent decades because of its ability to develop resistance to various antibiotics. A loop‐mediated isothermal amplification (LAMP) method for rapid and sensitive detection of E. faecalis in drinking water samples was developed and applied in this study. Four primers were specifically designed by targeting the mtlf gene. The mtlf‐based LAMP assay was able to specifically detect all of 54 E. faecalis isolates without amplification of 36 nontarget bacterial strains. The detection limit was 74 cfu/mL in pure culture, which was as high as 100‐fold more sensitive than that of the groES‐polymerase chain reaction (PCR) method. When applied to artificially contaminated water, the LAMP assay was able to detect E. faecalis with low concentration (3.2 cfu/250 mL), after 10 h enrichment culture. In the case of drinking water samples, 7.14% (7/98) of the samples were found to be positive by LAMP, which was in accordance with the results from the GB/T 8538‐2008 method. The LAMP assay established in this study may provide a candidate method for rapid and sensitive detection of E. faecalis in drinking water samples.Practical ApplicationsE. faecalis contamination in drinking water source and drinking water has been reported. In developing countries, such as China, the LAMP assay may prove as a useful tool for rapid assessment of water quality as it is more cost‐effective, simple and sensitive than PCR.

TDS-Eh graph analysis: a new water quality index and rural water supply implications of a river affected by mining in south-eastern Nigeria

The Ivo River Basin of south-eastern Nigeria is a water scarce and mining region, which suffers from water scarcity. The influence of mining activities on the quality of the Ivo River and its capacity for community water supply was investigated. Also the efficacy of TDS-Eh graph in explaining water quality was presented. Results indicated that the TDS-Eh graph highlights subtle chemical relationships which control water quality and provide a simple but generic pollution index for rapid water quality assessment. It was also discovered that the Ivo River could become an adequate alternative to groundwater as a source of rural water supply in the study area with an estimated average daily discharge of 6726000 L and a rural population of less than 200000 persons. The Ivo River meets the WHO drinking water standards in 20 physicochemical water quality parameters (pH, temperature, conductivity, turbidity, salinity, TDS, Eh, alkalinity, chloride, nitrate, sulfate, phosphate, calcium, magnesium, iron, manganese, zinc, lead and cadmium) analyzed and can therefore (with little treatment) provide up to 133.4% of average community water demand and 83.8% of maximum community water demand. The impact of mining on Ivo River quality was found to have been moderated by the presence of carbonate rocks which may have enhanced the precipitation of heavy metals from the river.

Usefulness of the hydrogen sulfide test for assessment of water quality in Bangladesh

To evaluate the usefulness of the hydrogen sulfide (H(2)S) test for assessing water quality in Bangladesh. We tested 382 water samples from a variety of sources using locally produced H(2)S test kits and laboratory-based membrane filtration for the detection of Escherichia coli. Compared with membrane filtration, H(2)S tests, when incubated for 24 h, had both a sensitivity and positive predictive value (PPV) of <40% when analysis was restricted to water samples with E. coli levels below 100 colony forming units (CFU) per 100 ml. In contrast, for E. coli levels from 1000 to 9999 CFU per 100 ml, sensitivity was 94% and PPV 88%; specificity was 97% and negative predictive value was 99%. The hydrogen sulfide test, when incubated at 24 h, is a promising alternative for assessing water quality where E. coli levels may be high. An improved understanding of the incremental impact of contamination level on health is needed to better determine its usefulness. The hydrogen sulfide test is inexpensive, easy to use and portable. Its use may allow rapid assessment of water quality in situations where cost or logistics prevent use of other testing methods, such as in remote areas or during flood and other natural disasters.

Molecular Assays for Targeting Human and Bovine Enteric Viruses in Coastal Waters and Their Application for Library-Independent Source Tracking

Rapid population growth and urban development along waterways and coastal areas have led to decreasing water quality. To examine the effects of upstream anthropogenic activities on microbiological water quality, methods for source-specific testing are required. In this study, molecular assays targeting human enteroviruses (HEV), bovine enteroviruses (BEV), and human adenoviruses (HAdV) were developed and used to identify major sources of fecal contamination in the lower Altamaha River, Georgia. Two-liter grab samples were collected monthly from five tidally influenced stations between July and December 2002. Samples were analyzed by reverse transcription- and nested-PCR. PCR results were confirmed by dot blot hybridization. Eleven and 17 of the 30 surface water samples tested positive for HAdV and HEV, respectively. Two-thirds of the samples tested positive for either HEV or HAdV, and the viruses occurred simultaneously in 26% of samples. BEV were detected in 11 of 30 surface water samples. Binary logistic regression analysis showed that the presence of both human and bovine enteric viruses was not significantly related to either fecal coliform or total coliform levels. The presence of these viruses was directly related to dissolved oxygen and streamflow but inversely related to water temperature, rainfall in the 30 days preceding sampling, and chlorophyll-a concentrations. The stringent host specificity of enteric viruses makes them good library-independent indicators for identification of water pollution sources. Viral pathogen detection by PCR is a highly sensitive and easy-to-use tool for rapid assessment of water quality and fecal contamination when public health risk characterization is not necessary.

Assessment of nitrogen leaching from arable land in large river basins: Part I. Simulation experiments using a process-based model

A two-step procedure for analysing nitrogen leaching from arable land in large river basins is suggested: (1) application of a process-based dynamic model for a set of representative conditions in a large river basin to simulate water and nitrogen fluxes and (2) development of a fuzzy-rule based metamodel using the simulated nitrogen fluxes in Step 1 as a training set. After that the metamodel can be used for rapid assessment of water quality inside the considered ranges of parameters, describing natural conditions and management practices. This paper describes Step 1 of the procedure. Step 2 is described in an accompanying paper (Haberlandt et al., Ecological Modelling 150 (3) (2002) 277–294). The advantage of this approach is that it combines the ‘process-based foundation’ with the resulting simplicity of the metamodel. Simulation experiments for analysing nitrogen (N) leaching from arable land were performed using the Soil and Water Integrated Model (SWIM) for a set of representative conditions in the Saale basin (23 687 km 2) in Central Europe. The Saale River is one of the main tributaries of the Elbe. In advance, hydrological validation of the model was done for the whole Saale basin and validation of nitrogen dynamics was fulfilled in two mesoscale sub-basins of the Elbe. For the simulation experiments the drainage basin area was sub-divided into five climate zones and nine representative soil classes were chosen. The basic rotation and fertilisation schemes were established using regional information obtained from literature. In addition, the effects of changing the basic rotation to more/less intensive ones and changing fertilisation rates by 50% increase/decrease were studied. The ranges of simulated nitrogen fluxes for the basic rotation and fertilisation schemes are comparable to available regional estimates and differences between sub-regions and soils are plausible. The relative importance of natural and anthropogenic factors affecting nitrogen leaching for the Saale River basin was as follows: (1) soil, (2) climate, (3) fertilisation rate and (4) crop rotation. The simulation experiments provide a basis for a fuzzy-rule based metamodel approach, which aims at rapid water quality assessment of large regions.