1217 results about "Fluvial" patented technology

An energy module comprising an energy absorber; and a mooring system, comprising a wing-shaped polymer shell attached to the energy absorber, the wing-shaped polymer shell designed to utilize the force of a passing current to create a downward force and thereby reduce any upward motion in the energy module; and a mooring cable housed inside the wing-shaped polymer shell and anchored to maintain the energy module in a fore and aft and a side-to-side position to provide stability, and to negate a rotational force on the energy module.

The invention relates to a method for calculating the tracing contribution of a sudden accidental water pollution source at a point source, which is effective in rapid tracing of a river basin and environmental management and protection of the river basin. The method includes: according to the natural geographical features of the river basin, determining the control area corresponding to the control section of the river basin; using the monitoring data of the pollution source and the statistical data of the pollution source to budget regarding the pollution source in the river basin; using a one-dimensional unsteady water quality model to establish the relationship between pollution source and water quality of the section; using the relationship between pollution source and water quality of the section to calculate the contribution coefficient of the pollution source within the river basin and characterizing the contribution of pollution sources. The method is novel and unique, easy tooperate and use, accurate in calculation, and high in efficiency, makes full use of the basic information of the existing pollution source, quickly feeds back the state of the pollution source in theriver control section in a short time, locks the pollution source which has relatively greater contribution to the river water quality in the river basin, provides the support for the pollution tracing of the river basin, and is effectively used for the environmental protection and treatment of the river.

The invention discloses an analysis and evaluation method for inrush mountain torrent disasters of regions without data, and relates to the field of mountain torrent disaster analysis and evaluation. The method comprises the steps that the basic information of a project area is obtained; the landform, the river position form and the flood control current situation of an evaluated object are obtained; the catchment area and runoff components of the dike confluence drainage basin of each small watershed in the obtained evaluated object are determined; rainstorm parameter calculation, rainstorm calculation and concentration-time-based rainstorm time interval distribution of the evaluated object are obtained; flood calculation is designed, and the water level and flow relation of a riverway section, prone to inrush, of the evaluated object is obtained; the riverway flood control current situation in the evaluated object is determined, and accordingly danger zone grade division is conducted; and an early warning point is established, the early warning water level of the analyzed and evaluated object is determined, and the early warning index of the analyzed and evaluated object is formulated. According to the analysis and evaluation method, the inrush mountain torrents serves as the main analyzed and evaluated object, and a current riverway flood control current situation evaluation method and an early warning index analysis method are provided.

The invention relates to an ecological restoration method for a city watercourse. The ecological restoration method for the city watercourse is characterized in that the polluted city watercourse is comprehensively restored with the combination of physical, biological and ecological technologies, the ecological theory is used for reference in the treatment process, the ecological idea is used as the guiding thought, a complex water ecosystem structure is constructed and restored, the original natural state of the watercourse is restored, the self-cleaning capacity of a river system is improved, the environment is beautified, and the local city microclimates are improved at the same time. The ecological restoration method mainly comprises the steps of (1) controlling a pollution source, (2) modifying the river bank, (3) optimizing the environment of the river bottom, (4) modifying the watercourse, (5) conducting aeration and oxygenation, (6) constructing an aquatic plant community, (7) constructing a fish and macrobenthos community, and (8) maintaining the system. The watercourse ecological system restored through the ecological restoration method has the certain anti-interference capacity, on the premise that a large amount of exogenous pollution is cut off, the certain-strength interference can be resisted, and the good ecological environmental effect is obtained. After one-time input, the better ecological benefit can be obtained only with a small number of maintenance costs.

The invention relates to the technical field of prediction of weather states, and especially relates to a modeling evaluation method for urban heavy rain inundation. The method includes the following steps: (1), establishing a to-be-evaluated area into a digital elevation model, and dividing the model into grids; (2), generating a river network, establishing a river network on the digital elevation model, and determining the current direction and speed of a basin; (3) determining inundated areas, the grids the river flows across being river grids and other grids being ground grids, determining initial river grids and inundation conditions, and successively determining, from the initial river grids, whether the ground grids adjacent the river grids meet inundation conditions, wherein the ground grids are inundated grids if the conditions are satisfied, otherwise, the ground grids are not inundated grids; (4) determining the inundation critical rainfall; (5) determining inundation calamity risks; and (6) evaluating inundation risks. Through adoption of the method, the inundation coverage, the inundation depth, the inundation risks and losses or the like can be predicated before heavy rain, early warning is carried out timely, property losses are minimized, and personal safety is guaranteed.

A high altitude pumped-storage system for selectively integrating, storing, and distributing water and energy to increase the regional productivity of existing and future water and energy resources throughout multiple river basins is disclosed. This system addresses in part the increased requirement of supplying energy demands from a renewable energy source, such as wind, solar, or water generated power. The system includes at least one primary reservoir connected to multiple secondary reservoirs by conduits. The system allows for selectively distributing water and energy between secondary reservoirs and at least one primary reservoir. The system may comprise one or more hydroelectric power generation facilities. A method for increasing the regional efficiency of existing and future systems for producing, storing, and delivering energy from sources such as hydroelectric, wind and solar power from the water collected by the system described herein is also disclosed.

A river course ecological treatment system essentially comprises a plurality of ecological biological water purification systems and a plurality of plastic retaining dams disposed along a river course, and at least one damp land ecological water purification system disposed beside the river course. The plastic retaining dams separate the river course into several retaining regions. The ecological biological water purification systems purify the water in the retaining regions by microorganism purification. Afterward, the water purified by the ecological biological water purification systems is introduced into rainwater channels of the at least one damp land ecological water purification system. After being purified by aquatic plants in the at least one damp land ecological water purification system, the water returns to the retaining regions the downstream portion of the river course. Therefore, a river improvement system capable of performing both step-by-step treatment and joint treatment is effectuated.

The invention relates to a method for constructing a deep pool and a shoal in a straight river channel. In the method, a spur dike is arranged on the left bank side of the straight river channel, a bank slope on the opposite bank of the spur dike is protected by riprap, a diving guide wall is arranged on the left and right banks of the downstream side of the spur dike respectively, the discharge cross section of the river channel is shortened by the spur dike to increase the flow rate of water flow, the bottom of a river bed of a river reach between the diving guide walls on the downstream side of the spur dike is continuously scoured to naturally form the deep pool, and a dead water area or slow flow water area formed between the diving guide wall and the river bank becomes the shoal through long-term deposition. The method has the advantages that: the deep pool is naturally formed and becomes a rest place for aquatic organisms such as fishes and the like, and can become a shelter for the aquatic organisms such as the fishes and the like in a flood period; plants can be planted on the shoal, and the shoal can become an organism habitat different from the deep pool; and the complexity of a river channel structure and water conservation condition diversity can be increased or repaired, and river biodiversity, population composition and rare species conservation are facilitated.

The invention discloses a construction method for ecological restoration of riparian vegetation of mountain rivers. The method includes the following steps: (1), for restoration of aquatic vegetation, dispersedly planting potamogetonaceae and hydrocharitaceae submerged plants high in washing-out resistance in a project region; (2) for restoration of riverway rock and boulder vegetation, planting wetland plants strong in washing-out resistance in rock and boulder regions and the like in a riverway in the project region; (3) for restoration of waterfront plants, planting emerging plants and aquatic plants with washing-out resistance and deep roots between the riparian normal water level and the two-year flood level in the projection region; (4) for restoration of riparian vegetation, planting waterlogging-tolerance trees and shrubs of juglandaceae, betulaceae and the like between the two-year flood level and the 20-year flood level in the project region, and planting gramineae and cyperaceae herbaceous plants with deep roots in ground covers. By the method, the ecological problems about riparian water and soil erosion, weak river's self-purification capacity, sharp decline in biodiversity and the like are solved effectively, feasible and effective ecological remediation measures are provided for natural restoration and reconstruction of river banks and riverways.

The invention relates to an automatic river and lake water sample control acquisition system based on a multi-rotor-wing unmanned aerial vehicle. The automatic river and lake water sample control acquisition system comprises a remote controller, the multi-rotor-wing unmanned aerial vehicle, a lifting device and a water sample acquisition device, wherein the lifting device is arranged on the multi-rotor-wing unmanned aerial vehicle, the water sample acquisition device is connected with the lifting device, a wireless receiver, a programmable logic controller, a navigation locating system, a camera and a wireless transmitter are arranged on the multi-rotor-wing unmanned aerial vehicle, the navigation locating system is connected with the wireless receiver, the wireless receiver and the wireless transmitter are both in wireless communication with the remote controller, and the wireless receiver, the wireless transmitter, the camera, the lifting device and the water sample acquisition device are all connected with the programmable logic controller. The automatic control acquisition system enters a sampling region in a flying manner, is flexible, and can prevent the problem that existing sampling equipment cannot enter the sampling region due to frondent aquatic plants in riverways, relatively low water level, complex sampling environments and the like, so that the sampling in a high-efficiency manner can be accurately performed.

It relates to the after potential exploration of an oil filed, with the ability of analyzing the oil distribution, left resource quantity, and so on. It comprises the data inspection device, data preprocessing device, KH value separation device, oil well water absorption preprocessing device, water absorption section separation device, dynamic personnel analysis separation device, small layer weighting separation device, single sand separation result accumulation device, data base, water filling effect, strata HK, and weighting of the oil reserve weighting by the dynamic personnel, determining the strata output through the water absorption section, water content of the strata through well fluid section, with the whole process being computerized and accurate.

A method and system is provided for producing erosionally stable fluvial geomorphic landscape designs in a computer aided design environment. A topography input module is configured to access a three-dimensional model of existing topography of a site, while a data input module is configured to receive climatic and hydrological data associated with the site. A channel geometry module is configured to utilize the three-dimensional model and the data to generate dimensions for one or more proposed ephemeral channels. A design surface module generates a graphical view of a proposed landform at the site using the existing topography, the proposed ephemeral channels, and optionally, various complementary topographic features.

The invention relates to a multi-dimensional filler ecological type protected slope construction method suitable for repairing riverways in towns. The method comprises the following steps of: taking an ecological bag structure as a support; dividing a protected slope structure into four areas: an upright protector area, a low water level influence area, a normal water level influence area and a maximum flood level influence area; selecting matrixes adapted to structures and functions of the areas as fillers; recovering submerged plants, emergent aquatic plants and wetland plantsbog plants on a protected slope from bottom to top; and simultaneously, setting facilities such as a buffering platform and a domestic sewage distribution pipe, and constructing a zigzag river corridor. According to the multi-dimensional filler ecological type protected slope construction method suitable for repairing the riverways in the towns, the mechanical stability of the slope can be improved, the anti-erosion performance of the protected slope of a river is enhanced; the living condition of a river waterside variation area is effectively recovered, and the completeness of a river ecological system is ensured; and the matrixes of the protected slope, microorganisms and vegetation have important interception conversion effect on coastwise non-point source pollution, so that the river self-cleaning capacity is enhanced, the service function of a river ecological system is improved, materials are selected according to circumstances, the construction is simple and convenient, the manufacturing cost is low, and wide market value and environmental benefit are realized.

The invention relates to scouring model experimental device of underground silt and method, which belong to the technical field of characteristic tests of hydraulics, river dynamics and soil and rockmechanics. The device comprises a scouring tank, a fixing table, a tilting device and a freezing tank. The method comprises the following steps: putting or stacking experimental soil samples or sand samples in the scouring tank; closing the scouring tank; starting a water flow for scouring the underground silt in a model experiment; shooting and recording a scouring process; closing the water flowand maintaining original water pressure when the scouring reaches a certain experimental state; then, freezing the scouring tank and the scouring samples by the freezing tank; labeling, positioning and cutting frozen scouring sample grids; and individually measuring, thawing, weighing and screening second-state frozen small samples to obtain the graduation of scouring models of the underground silt and the distribution of porosity in a scouring state. The scouring model experiment of the underground silt is carried out in a laboratory. The invention provides a reference and a theory for mutually stacking the silt, damming by sand stone and banking for preventing flood for river ways and is applied to the laboratory research of scouring the underground silt.

The invention provides an integrated device for sampling and layered-gradient research of lake or stream sediments, mainly comprising a sampling and layered-gradient research integrated tube, a constant-temperature lighting system, an exchange system for inlet water and outlet water, a dissolved oxygen control system, an online monitoring system, and a hydropower disturbance system. The invention has the advantages that the sampling tube and the layered-gradient research device are integrated into a whole, thus reducing the artificial disturbance as much as possible to keep the original characters of overlying water and sediments; and the real-time, layered, and non-disturbance observation and sampling can be realized by using the sediment simulator. The device of the invention can be applicable to the research on the change rules of physicochemical characteristics and biological properties of sediments and overlying water in various layers under the condition that the aquatic environment, like simulation temperature, light irradiation, and water body exchange, varies.

An image obtained when a rare or valuable thing is found is shared between users each wearing an image display apparatus on the head or face.When a man finds a rare or valuable thing, the man feels like telling it to his / her surroundings. For example, when the man finds a planet such as Venus or shooting stars in the night sky, fish or a fresh water crab in a pond or a river, a bird, a cicada, a unicorn beetle, or the like on a tall tree in the woods, the man feels like saying “Look there!” An image display apparatus 100 releases a captured image in a line-of-sight direction of the user to share a user's precious experience with other users.

The invention discloses an ecological comprehensive treatment system of a northern mountain river channel. The system comprises three sub ecological systems of an ecological permeable dike built on the upstream of a main stream and a branch stream of a mountain river, a reservoir pond arranged at the middle and downstream area of the mountain river and a wet land communicated with the reservoir pond, and adopts an ecological treatment mode of closure-storage-preservation. The construction method comprises the steps of: a) building of the ecological permeable dike; b) setting of a triangular pyramidal wood pile stone cage; c) building of the reservoir pond; d) planting of plants of the reservoir pond; e) building of a wet land system; and f) recovery of a river bank band. The system and the construction method can effectively intercept the mountain debris flow and the river non-point source pollution, adjust the river runoff, improve the hydrologic conditions of the mountain river in non-flood season, decrease the dry season of the mountain river, and facilitate to recover the ecological system of the mountain river. Meanwhile, traditional depressions and empty ponds in the mountain river can be used in construction, so that the engineering building cost is reduced, and the self-cleaning capacity of river water is improved.

The invention discloses a river critical levee section washing safety analysis and bank slope stability judgment method. The method comprises the steps of 1, generating a data set used for constructing a two-dimensional river channel water / sand model; 2, setting model calculation parameters and definite solution conditions according to river reach parameters in the research area, and constructing a two-dimensional water / sand numerical simulation model of the research area; step 3, setting various working conditions according to sand coming conditions under different flood conditions, simulating river water / sand transportation and river bed silt flushing of a research area by utilizing a two-dimensional water / sand numerical model, analyzing dangerous river beds before and after flood based on a simulation result, and respectively calculating river dangerous bank slope river bed depth flushing distance and river lateral erosion distance; and step 4, constructing a finite element model for seepage-stability analysis of the bank slope of the critical levee section, and quantitatively researching the relationship between each factor and the bank slope stability safety coefficient. According to the method, the stability of the riverway dangerous work bank slope under the action of water flow flushing is studied, and a quantitative means is provided for critical levee section stability evaluation.

The invention discloses a multi-basin real-time intelligent water quality predication method and system. According to the multi-basin real-time intelligent water quality predication method and system, an NARX model is optimized through a genetic algorithm and a problem that earlier stage parameters of the NARX model are uncertain; a GA-NARX model is stored or called through a model storage module to predicate the multi-basin water quality condition in real time; essential data, recent data and history emergency data are performed on three-section training and accordingly an optimized GA-NARX model can basically comprise river pollution characteristics and the predication accuracy is improved; weather data replaces hydrological data and is performed on obfuscation processing and accordingly influences to the model from flow data missing are effectively solved; matching of similar pollution time sequence templates is performed through an improved DTW algorithm, a similar pollution process in the basin history is rapidly found out, experience is referred and learned, and sudden emergency accidents are accurately predicted. The multi-basin real-time intelligent water quality predication method and system can be widely applied to the water quality predication field.

The invention provides an ecological restoring method of a river water body, comprising the following steps: (1) detecting pollution indexes of a river water body; (2) throwing composite microbial agents into a water body according to 5ppm to 9ppm; (3) transferring, translating and degrading matters in the river water body by the composite microbial agents; (4) throwing and / or planting water plants into a river; (5) detecting the pollution indexes of the river water body; and (6) repeating the steps from (2) to (5) from 15 days to 30 days until the river water body conforms to requirements. Each composite microbial agent comprises the components by weight percent: 5 to 10 photosynthetic bacteria, 10 to 15 bacillus subtilis, 5 to 10 nitrifying bacteria, 2 to 5 microzyme, 15 to 20 lactobacillus, 10 to 30 aspergillus, 10 to 30 acetobacter and 20 to 30 actinomyces. The ecological restoring method of a river water body aims at a river water body which carries out eutrophication treatment, leads the river water body to restore the bio-diversity of the river water body, radically restores ecology and has durable effect, low cost and simple use.

The invention discloses an analysis method for identifying main influence factors on water qualities of rivers flowing into the Tai Lake on the basis of a PSO (Particle Swarm Optimization) and SVM (Support Vector Machine) hybrid algorithm and belongs to the technical field of water quality monitoring. In the method, a PSO algorithm is combined with an SVM algorithm; the PSO algorithm is used for optimizing parameters c and g of the SVM algorithm so as to rapidly and efficiently determine global optimums of the c and the g; and based on the optimized c and g, the SVM algorithm predicts different water qualities by using masses of influence factors influencing the water qualities as eigenvectors and identifies and determines the main influence factors on the water qualities of the rivers flowing into the Tai Lake through the predictive rate. By the method, the main influence factors can be accurately identified from various influence factors influencing the water qualities so as to provide beneficial proofs for monitoring early-warning of the water qualities of the rivers.

The invention discloses a water supplement and algae control method for a large-scale shallow lake water bloom agglomeration water area. The method utilizes a water environment simulation technology, a soft enclosure technology and a dynamic monitoring and scheduling technology and comprises building a lake water environment analogy model, constructing soft enclosure engineering to form a desired water area, carrying out on-line monitoring on the desired water area, building a space-time high precision water environment analogy model of the desired water area, constructing a water quality neural network model and building a flow scheduling system of a water supplement river. The method is a systematic and quantitative technical system which utilizes a river flowing into lake to supply water for a large-scale shallow lake water bloom agglomeration water area so that algal density is controlled. The method builds a defined quantification relationship between supplement water amount and quality and water quality response of a desired water area so that quantitative water environment in the water resource scheduling system is realized, and the problem that the existing water diversion-based alga control engineering measures cannot form a quantitative technical solution so that alga control effects are uncertain or unconspicuous is solved.

The invention relates to a method for river course slope protection by using composite stream constructed wetlands, comprising the following steps that: (a) grass planting ditches with V-shaped cross section are dug on a slope surface, and plants are planted in the grass planting ditches; (b) a composite stream constructed wetland in which fillers are provided is set at the water outlet of the grass planting ditch, and one or more plants selected from reeds, cattail, sedge, Sparganium, Juncus, canna, metasequoia, calamus, Scirpus tabernaemontani, arrowheads, Aponogetonaceae grass, Alternanthera sessilis, cress or sedge are planted on the fillers; (c) a water outlet pipe is arranged at one side of the composite stream constructed wetland adjacent to the river course so that water flowing from the composite stream constructed wetland is drained into the water course. The method for river course slope protection by using composite stream constructed wetlands has the advantages of good stability of slope protection to water courses, little damage to ecological environment keeping at both sides of rivers, capability of beautifying riparian landscape and adding biological diversity, low cost and favorable pollution interception and purification effects.

The invention discloses a Binjiang touring type wetland revegetation mode structure. The Binjiang touring type wetland revegetation mode structure is characterized in that in a river bank, an aquatic plant purifying region is arranged below a high water level, a water edge soil fixation and erosion preventing region is arranged above the high water level, and an overwater forest recovery region is arranged on one far-water side outside the erosion preventing region. In the aquatic plant purifying region, aquatic floating-leaved plants are planted below a normal water level in a naturally scattered growth and close planting mode, and high-stalk emerged plants are planted above the normal water level and below the high water level in a naturally scattered growth and close planting mode. The water edge soil fixation and erosion preventing region is paved with slope protection bricks and the width of the water edge soil fixation and erosion preventing region ranges from 2m to 3m. The overwater forest recovery region is of an ecological simulation community structure formed by natural mixing of wetland trees and shrubs to achieve height matching, color combination, advantage and disadvantage complementation and calobiosis. Touring footpaths and seats for rest are naturally arranged in the river direction in communities. Through meticulous engineering design and scientific plant matching, the Binjiang touring type wetland revegetation mode structure achieves perfect combination of Binjiang hydraulic engineering and wetland revegetation, is important for river bank wetland soil fixation and erosion preventing and environment improvement, and has the advantages of being ecological, beautiful and multifunctional and increasing effect.

The invention discloses a desert riparian forest spatial distribution obtaining method based on GIS buffer area analysis, wherein the method belongs to the field of drought area vegetation remote sensing technology. The method comprises the following steps of a first step, downloading a TM remote sensing image of a location with a drought area river, performing image preprocessing, remote sensing interpretation and NDVI calculation on the remote sensing image, and obtaining NDVI remote sensing data of the desert riparian forest; a second step, extracting a riverbank boundary vector line, and performing unified registering and correction on the remote sensing image in a GIS platform; a third step, generating a riverway peripheral multiple-buffer-area vector picture according to a research requirement; and a fourth step, overlapping the multiple-buffer-area vector picture and the NDVI remote sensing data of the desert riparian forest, extracting an NDVI mean value in each buffer area, using a vertical riverawy distance as an independent variable and using the NDVI mean value as a dependent variable, and performing desert riparian forest spatial distribution structure analysis by means of curve fitting. The desert riparian forest spatial distribution obtaining method supplies a beneficial reference for determining continuous gradient distribution of the desert riparian forest and the protecting range thereof.

A non-powered drain pump screen device is disposed in a river, a stream, a waterway, or a place in which a significant amount soil is carried by a water flow. Upper and lower impellers are provided with upper and lower blades. The lower blades prevent reentry of impurities while rotating due to resistance to a flow of fluid in a non-powered manner. The upper impellers are rotated in a non-powered manner, so that the upper blades filter impurities. The non-powered drain pump screen device is disposed in a waterway to remove impurities at low maintenance costs.

The invention discloses an automatically extracting method for the river-valley morphological parameters based on DEM, and relates to the field of digital geomorphology analysis. The automatically extracting method includes the steps that DEM data for analyzing a river-valley drainage basin is obtained; all rivers belonging to the river-valley drainage basin are obtained and numbered, and sampling points of a longitudinal section are taken at a certain sampling interval a; the morphological parameters of the longitudinal section of a river valley and the morphological parameters of the transverse section of the river valley are calculated. By means of the automatically extracting method, river-valley geomorphology and subsection difference can be represented in the microscopic view, and the whole terrain of the river valley can be analyzed; representation is comprehensive; the calculated parameters are small in interference factor and high in accuracy and operation efficiency.

The invention discloses a safe and fast construction method of a down-traversing river shallow depth bored tunnel. The method includes the steps that on the two sides of the tunnel, the upstream and the downstream of a river are each provided with a clay cofferdam so that the river can be intercepted, and a dry river bed is formed in a tunnel construction area; the two constructed clay cofferdams are communicated through a flow guiding pipe, and therefore upstream river water and downstream river water can flow; the two sides of the tunnel are each provided with at least one row of Larsen steel plate piles, and the tunnel is excavated after the Larsen steel plate piles extend to a river bank in the axial direction of the tunnel. The clay cofferdams, the flow guiding pipe and the Larsen steel plate piles are matched coordinately and comprehensively utilized, and tunnel construction safety is guaranteed by the clay cofferdams, the flow guiding pipe and the Larsen steel plate piles jointly. The method is good in construction safety and high in construction efficiency, treatment measures are flexible, pertinent adjustment can be performed according to different geological conditions, and manufacturing cost of projects is saved as much as possible on the premise that safety is guaranteed.

The invention relates to a multifunctional modularized floating island for in-situ restoration of polluted rivers and lakes. The floating island consists of five functional modules including a waterscape floating island module, a flexible filler floating island module, an aeration floating island module, a power supply floating island module and a functional floating island module. Each functional module is formed by floating beds in the same shape and size; different functional components are matched on the floating beds respectively so as to form the above functional modules. 2-5 different functional modules are selected in proportions according to the water quality difference and area load of the polluted river, and are optimally combined, thus various micro-environments are formed along the water flow direction, the self-cleaning ability of rivers and lakes are prompted, and the COD (chemical oxygen demand) and ammonia and nitrogen of the polluted water can all reach the V-type standard of surface water. With the adoption of the technology, the problems of single function, poor applicability and low water quality improving efficiency of the plant floating island structure in the prior art are solved, and the in-situ high-efficiency water quality improvement of water in polluted rivers and lakes is achieved.