127 results about "Design flood" patented technology

The invention discloses a method for deriving and designing a flood process line based on a multi-variable most possible condition combination. According to the method, two-dimensional to multi-dimensional joint distribution functions of a flood peak and flood volumes at different time periods are constructed through a Copula function; a calculating expression formula for the most possible condition combination of under different dimensions is deduced; an estimation value of the most possible condition combination of the flood peak and the flood volumes are solved by taking a maximum condition probability density function as a principle; a single-variable condition recurrence period serves as a designed flood recurrence period standard, so that designed flood process lines at different design frequencies are derived. The method disclosed by the invention is scientific and reasonable, and is closer to real engineering, and can provide an important and high-operability reference basis for deriving and designing the flood process lines of a water reservoir.

The invention discloses a complex step reservoir group water storage period optimized scheduling method which comprises the steps of S1, collecting basic information of a river basin; S2, dividing a complex step reservoir group into a plurality of sub-river-basin areas, and respectively calculating an after flood season of each sub-river-basin area; S3, estimating a probability that the flow of a branch flood prevention node exceeds a safe flow in each sub-river-basin area, and demonstrating feasibility of seasonal flood end water storage scheduling optimization by means of the probability; S4, constructing a multi-target water storage scheduling optimization model; S5, solving the multi-target water storage scheduling optimization model by means of a Pareto dynamic dimension searching method, and obtaining a certainty optimization scheduling result of a seasonal flood end water storage period; S6, extracting an optimization scheduling rule of the seasonal flood end water storage period by means of a large system polymerization / decomposition model; and S7, performing flood prevention safety examination on the optimization scheduling rule through using river basin designed flood as an input. The complex step reservoir group water storage period optimized scheduling method is a new method for complex step reservoir seasonal flood end water storage period optimized scheduling under a precondition that a flood prevention standard of the basin is not reduced.

The invention belongs to the field of flood control safety design of reservoirs, and relates to a method of determining downstream design flood of cascade reservoirs. The method comprises the following steps that by the adoption of the Copula function, multi-dimensional simultaneous distribution of the section flood volume and the regional flood volume of the reservoirs is constructed, the explicit expression of a conditional probability function is deduced, the frequency curve of the conditional probability is dispersed, and according to the principle of probability combination discrete summation, the design value and the corresponding probability of the annular maximum peak discharge of downstream sections are determined after flood regulation is conducted through the cascade reservoirs. The method can overcome the defects of traditional determination technologies of the design flood of the cascade reservoirs, and provides more comprehensive reference information for cascade planning and development of drainage basins.

The present invention relates to a river basin design flood inference method based on a conceptual hydrological model. The method comprises the following steps: Step 1, collecting and processing dataof a typical stormwater process; Step 2, selecting and determining a conceptual hydrological model; Step 3, determining the applicability of the hydrological model in the study of the basin; Step 4, substituting the applicability to design the storm to obtain the design flood; and Step 5, comparing the instantaneous unit line method with the original design result of the project for referential evidence. According to the method provided by the present invention, experiential generalization in the original design flood calculation is improved, characteristics of the production and sink flow inthe basin are analyzed based on the theory of the rainfall runoff in the river basin, and based on the applicability of the hydrological model, the design flood is deduced from the physical mechanism;and the method improves the design flood theoretical system and is a new method for calculating the design flood that can be used for promotion and application.

The invention discloses a reservoir multi-variable design flood estimating method for achieving self-adaption to weather changes. A coupled model of a GCM and a VIC is built to predict the reservoir runoff process on the scene of future weather changes. A reservoir design flood peak volume most possible combination method calculation model is built through a Copula function, and reservoir predicted runoff data on the scene of the future weather changes serve as input of the design flood peak volume most possible combination method calculation model, and a combination design value of a reservoir at different recurrence period levels is calculated. The reservoir multi-variable design flood estimating method has a strong statistics basis, the characteristics of an actual measurement sample can be objectively reflected and the internal relatedness of the characteristic quantities is taken into full account. The design flood design value obtained under the condition that the weather changes are considered has higher practicability.

The invention relates to a computing method for design storm flood of mountain flood disaster small watersheds. The computing method comprises the following steps: 1) computing concentration time t diachronic design area rainfall of a representative station; 2) performing rainstorm duration distribution on the t diachronic design area rainfall to obtain a design rain pattern with a time period length of 1 hour; 3) substituting the design rain pattern into a design flood model to obtain the design storm flood, and selecting the design flood model through regional synthesis; and 4) obtaining the design storm flood of other small watersheds of a region according to the design flood model. The rainstorm attenuation index parameter is improved, so the design storm computing method is suitable for the small watersheds; the computing method is determined for the other small watersheds of the region through the regional synthesis; and the accuracy of a computing result is ensured by realistic correction.

The invention provides a method for inquiring into a design flood hygrograph. The method includes the steps that the first frequency is determined to be the standard frequency; under the standard frequency, the design flood hygrograph is obtained; on the premise that it is ensured that the design flood peak and the design flood volume in the design flood hygrograph are not changed, the smooth standard design flood hygrograph is obtained by conducting smoothing on a zigzag area on the design flood hygrograph; the standard design flood peak and standard design flood amounts of all duration time periods are obtained according to the standard design flood hygrograph; the standard design flood peak serves as the flood peak of typical floods, the standard design amounts of all the duration time periods serve as the flood amounts of the typical floods of all the duration time periods, and the design flood hygrograph of at least one second frequency different from the standard frequency is inquired into.

The invention provides a permeable overflow dam combining functions of water level control and water purification, which comprises a solid dam body, a permeable dam body and water purifying media arranged in the permeable dam body, wherein the solid dam body is in a water-proof solid structure formed by casting concrete or reinforced concrete, and the height of the dam top of the solid dam body is the height of a higher water level in the lowest water level required by a river channel ecological system or the lowest water level required by river channel landscape environment; the permeable dam body is a lattice fence formed by casting concrete or reinforced concrete, a plurality of reinforced concrete partition walls are cast in the permeable dam body along a river width direction, a plurality of no-fines concrete walls are cast in the permeable dam body along a water flow direction, and the height of the dam top of the permeable dam body is higher than the designed normal water level of the overflow dam and is lower than that of the designed flood level of a river channel; and the water purifying media are pebbles, vermiculites, zeolites or spherical water purifying fillers. The invention not only can meet the requirement of raising the water level without influencing the flood discharge capacity but also can effectively purify water and improve river water environment quality.

The invention discloses a small-watershed design flood calculation method. The small-watershed design flood calculation method sequentially comprises calculation of design storm, calculation of runoff and calculation of confluence; according to Froude coefficients of different channel segments of a watershed, the whole watershed is classified; if the Froude coefficient of a certain channel segment of the watershed is greater than or equal to 1, it shows that the channel segment belongs to an upstream hill river; confluence of the upstream hill river is resolved by adopting a reasoning formula method; if the Froude coefficient of a certain channel segment of the watershed is less than 1, it shows that the channel segment belongs to a downstream plain river; and confluence of the downstream plain river is resolved by adopting a unsteady flow method. According to the small-watershed design flood calculation method disclosed by the invention, the characteristics and the water flow characteristics of the upstream hill river and the downstream plain river in the small watershed are distinguished; calculation is carried out by adopting different runoff and confluence calculation methods; and thus, an obtained design flood value is more reasonable and accurate.

The invention discloses a two-dimensional unsteady-flow numerical model based power engineering location method. On the basis of a plurality of site locations primarily selected according to design requirements of a power grid transmission line, the two-dimensional unsteady-flow numerical model is subjected to verification, parameter modification and design flood simulation by determining a simulation area, digitizing the simulation area and establishing the two-dimensional unsteady-flow numerical model and historical flood data, the site locations primarily selected are sorted according to largest submerged depth, and a primary selection sequence of the site locations is obtained. By the two-dimensional unsteady-flow numerical module flood routing technology, hydrologic characteristics in a certain area and flood hydraulic elements during simulation of flood routing can be truly and objectively reflected, flood control safety of electric power engineering can be guaranteed, construction accuracy can be improved, land source consumption can be reduced, and construction cost can be lowered.

The invention discloses a typical- empirical-model-based emergency flood forecasting method. The method comprises: a statistical analysis is carried out on historical practically-measured flood elements to form a basic basis data set for emergency flood forecasting; refining processing is carried out on floods below a once-in-a-ten-year level by using an interpolation method and a designed flood process line table is obtained according to a refined interpolation method; view processing is carried out on main relevant elements of historical practically-measured floods and a historical flood scatter diagram is established by using values of process precipitation P plus early-stage influence rainfall Pa as horizontal coordinates and flooding starting flows as longitudinal coordinates; and according to the historical practically-measured floods and designed flood characteristics values, qualitative and quantitative water-break forecasting is carried out. Therefore, forecasting can be carried out timely and accurately under any circumstance; the timeliness and integrity requirements on drainage basin rainfall data by real-time flood forecasting can be reduced; and the method is simple and is easy to implement.

The invention discloses a small watershed design flood derivation method. The method comprises steps of determining a downstream hydrological station of the small watershed, and obtaining informationincluding a watershed DEM map above the hydrological station and the like; loading the obtained information into GIS software, extracting a drainage basin water system, cutting and dividing the drainage basin water system into a plurality of natural sub-drainage basins, endowing hydrological identification numbers, adding hydrological units and generalizing a drainage basin map; obtaining the rainfall runoff process of the annual maximum-session flood of the outlet section of the basin above the hydrological station; establishing a hydrological model of the watershed above the hydrological station; therefore, small-watershed hydrological model parameters capable of reflecting rainfall runoff process information of the small watershed of the to-be-deduced design flood are obtained, the design rainstorm of the small watershed is calculated through a hydrological frequency calculation method, and the design rainstorm is brought into the calibrated small-watershed hydrological model to deduce the design flood process line of the small watershed. According to the method, high-precision design flood capable of reflecting rainfall runoff process information of the small watershed can be obtained through simple operation in the small watershed.

The invention relates to a method for investigating no historical data small watershed through a flood frequency curve. The method comprises the following steps that: determining the boundary of a design drainage basin on a work map, selecting one or a plurality of design sections in the design drainage basin, and calculating drainage basin feature values including the area of each design section, a river length gradient and the like; using a rainfall contour line and a variation coefficient contour line to calculate the design storm of each design section in the drainage basin; adopting a reasoning formula method to investigate design flood according to the rainstorm of the design section, and calculating the flood of the design section; drawing the frequency calculation achievement point of each design section on Haisen frequency paper to obtain the flood frequency curve of each design section in the small watershed of a no-data area; and according to existing flood, checking a flood frequency curve, and determining the flood recurrence interval. By use of the method, a basis is provided for carrying out next computer programming, conveniently determining the design flood and determining the flood recurrence interval.

The invention discloses a reservoir group multi-objective action mechanism and optimized dispatching scheme analysis method. The reservoir group multi-objective action mechanism and optimized dispatching scheme analysis method comprises the steps that first, on the basis of a reservoir group system of a generalization study area, a five-objective optimized dispatching model of power generation, water supply, ecology, shipping and flood control of a reservoir group is constructed; a objective function and a constraint condition used in the model are determined, the flood control requirements are converted into a flood season water level constraint condition, the actually measured flood data or the designed flood process are used as model input, an intelligent optimization algorithm is usedfor solving the model, and the two-to-two objective two-dimensional planar mapping is carried out on solution results; the action relationship between the objectives under the incoming water conditionis subjected to nature-determining based on the relationship presented by the two-dimensional planar mapping, combined with the target function value corresponding to a selected representative point,the strength of the action relationship between the objectives under the incoming water condition is analyzed, discrimination of the action relationship between the objectives is carried out, and a reservoir group dispatching method is obtained. The reservoir group multi-objective action mechanism and optimized dispatching scheme analysis method provides reference and basis for the optimized dispatching of the reservoir group considering the benefits of power generation, water supply, ecology and shipping meanwhile, and high practicability and wide applicability are achieved

The invention discloses a method for protecting the river bank by a sand-river pile group and flexible mattresses, which comprises the step of arranging flexible mattress protective structures along the banks of the river, and is characterized in that the pile group consisting of at least two rows of protective piles is also arranged outside the side edge of the river bed in which the flexible mattress protective structure is arranged and used for protecting the river bank. When the method is specifically implemented, the flexible mattress protective structure generally can extend to the position 8 to 17m under the underwater river bed, the protective piles adopt concrete square piles, the lower end of each concrete square pile is rooted in the position about 10m under the bottom of the river bed so as to make the protective pile keep stable, and the height of the upper end of each concrete square file exceeds the design flood level. In the method, the pipe group arranged in the river bed outside the flexible mattresses can make a downstream and dank effect, and make the flow velocity of the water greatly slow down after flowing through the pile group by the streaming function, thereby reducing the scouring capability of the water flow and avoiding the damage to the flexible mattresses so as to achieve good bank protection effect.

The invention discloses a staging design flood derivation method in an integrated climate mode. The staging design flood derivation method comprises the steps: establishing a coupling model of a GCM and a VIC so as to predict the reservoir runoff process under the future climate change scene; through an arithmetic average method, obtaining an average state runoff process under a climate change scene; analyzing the runoff process by adopting a probability variable point method to divide a main flood period and a non-main flood period; constructing a reservoir design flood peak quantity most possible combination method calculation model through a Copula function; and taking reservoir prediction runoff data under a future climate change scene as input of a designed flood peak quantity combination method calculation model, and meanwhile, calculating the united design values of the reservoir under different recurrence period levels by considering multivariate same-frequency combination and most possible combination. The staging design flood derivation method has a strong statistical basis, and provides a new way for staged design flood calculation under a climate change scene.

The invention relates to a flood redistribution method for calculating corresponding cascade reservoir group design flood in a same-frequency region composition method, which adopts the proportion of the instantaneous flow rate in a region flood process of various nodes in a typical process and the instantaneous flow rate of corresponding flood process for redistribution of the corresponding flood process. The flood redistribution method provided in the invention better solves the problem of corresponding flood redistribution in the same-frequency region composition method, provides an effective path for corresponding flood distribution work of multiple regions hereafter, fully utilizes the typical flood process composition of various regions and also can meet the water balance requirements of all over the basin during the flood routing control interval.

The invention belongs to the technical field of flood forecasting, and relates to a method for inquiring the stage design flood of a reservoir. The method comprises the following steps: flood information with randomness and regularity is converted into directional data by applying a round fractional step method, and determining the stage time intervals of the reservoir by calculating a vector average angle, average radius and concentration ratio of the directional data; establishing a trivariate combined distribution model based on a three-dimensional asymmetric Copula function for constructing edge distribution to be P-III type distribution, and analyzing the correlation among stage flood by applying the trivariate combined distribution model; determining a deterministic relationship between the reservoir stage design flood frequency and a flood control standard by applying the trivariate combined distribution model; and finally determining the stage design flood frequency and a design value. According to the method, the defect of a conventional design flood inquiry technology can be overcome, so that the result can fulfill the flood control standard and can reflect the seasonal regulation of the flood.

The invention relates to a flood control risk assessment method for a left bank area of an engineering area in a water transfer project, which takes a catchment basin corresponding to a hydraulic structure involved in the water transfer project as an assessment unit, and comprises the steps of original flood control design condition change assessment, analysis of influence of basin underlying surface change on design flood, and evaluation of the flood control risk of the engineering area; wherein calculation is carried out to obtain a flooding area, a flooding water level and a flooding water depth by aiming at the units with flood control design conditions changed compared with the original design and influence of basin underlying surface condition change on the design flood, and the flood economic loss and population influence consequences are evaluated. The method has the beneficial effects that by adopting a systematic and scientific risk assessment method, flood control influence risks of catchment basins corresponding to various types of buildings involved in a water diversion project can be quantitatively assessed. The method comprises analyzing and evaluating the change degree of an existing actual flood discharge condition compared with an original flood control design condition, the change of design flood, the submerged depth and the submerged range of an evaluation unit which influences the watershed design flood due to the change of the original flood control design condition and the change of an underlying surface, and the influence of corresponding social economy, population and the like; therefore, scientific and technical support is provided for flood control and disaster reduction and planning and construction of hydraulic engineering.

The invention discloses a water diversion and silt prevention system for a convex bank. The water diversion and silt prevention system comprises a water guiding channel and a guiding wall which are arranged at the convex bank of a riverway, one end of the water guiding channel is provided with a water taking opening, the water taking opening is arranged inversely according to the flowing direction, the other end of the water guiding channel is provided with a plurality of sand guiding sills, the water taking opening is 2-4 times longer than the guiding wall, a front one third portion of the height of the guiding wall is a design flood level, the rear two thirds portion of the guiding wall is lower than the front one third portion of the guide wall, the sand guiding sills are straight line sand guiding sills, the sand guiding sills are parallel to one another, an inclination angle of 35-45 degrees is formed between the sand guiding sills and the flowing direction of the riverway, the length of the sand guiding sills is one second of the width of the water taking opening, and the number of the sand guiding sills is 3-5. The water diversion and silt prevention system is simple in structure, the silt preventing efficiency is good, and the water diversion is guaranteed.

The invention discloses a design flood derivation method and system based on equal reliability in a climatic change scene. The invention belongs to the field of reservoir flood control safety design.A future climate change scene is obtained based on global climate mode output and a two-stage deviation correction method considering meteorological variable correlation; a VIC distributed hydrological model is driven to obtain a runoff situation considering the influence of climate change; a principal component analysis method is adopted to preferably select an extreme rainfall index influencingflood characteristics as a covariable; a time-varying hydrological frequency analysis model is constructed by considering inconsistency of a flood sequence, a flood design value combination under a climatic change scene is deduced based on an equal reliability method, a most possible value is adopted as a final design value, and a 95% confidence interval is selected to estimate uncertainty of thefinal design value. According to the method, the influence of climate change on flood characteristics can be fully considered, and an important reference basis with high operability can be provided for deducing adaptive design flood in a climate change scene.

The invention provides a rapid-slow flow smooth transition flow diversion system for a riverway intersection area. The structure of the rapid-slow flow smooth transition flow diversion system for the riverway intersection area is as follows: a hydraulic jump energy dissipation section is arranged on a rapid flow channel in front of intersection of two channels, and a streamline channel wall is arranged between the hydraulic jump energy dissipation section on the rapid flow channel and a slow flow channel; a jet flow control structure is composed of a fish mouth and a flow diversion wall, wherein the flow diversion wall is arranged at the top end of the fish mouth and is parallel with the slow flow channel; the fish mouth is arranged at an intersection point of the connection of the streamline channel wall and the slow flow channel and extends toward a slow flow channel center and extends to a stable flow diversion channel. The rapid-slow flow smooth transition flow diversion system for the riverway intersection area has the advantages that the phenomenon that large standing waves are formed when rapid flow directly enters the slow flow channel can be avoided, and channel flood discharge is benefited; the direction of the flow of the rapid flow channel can be changed stably, and the form of a flow line is changed smoothly; flow separation and vortexes are weakened and even eliminated, and the actual flow discharge area is increased; the jet flow control structure effectively lowers the water level of an affluxion mouth; the channel design flood discharge flow quantity is guaranteed, and the water level of the affluxion mouth is effectively controlled; and the rapid-slow flow smooth transition flow diversion system for the riverway intersection area is beneficial to popularization in a large area in areas with limited land and in city flood-prevention projects, and the expropriation of the land is greatly reduced.

The invention discloses a non-uniform design flood calculation method. The method comprises the following steps: constructing a drainage basin actual measurement flood sequence by adopting an annual maximum value method; carrying out inconsistent flood frequency analysis by taking the cascade reservoir index RI as a covariable; determining statistical parameters of a future period according to thedrainage basin future period hydraulic engineering plan, and obtaining flood probability distribution of the future period; calculating a design flood value of a certain recurrence period under a non-uniform condition; and performing uncertainty analysis of non-uniform design flood calculation. According to the method, non-uniform design flood calculation is carried out based on the associated cascade reservoir group regulation and storage factors, and the effect is better than that of a time covariable model; according to the method, based on the ENE concept, the unique design flood magnitude corresponding to a certain recurrence period under the non-consistency condition is solved, and a powerful reference can be provided for non-consistency design flood and uncertainty calculation of the non-consistency design flood of a drainage basin with the obvious water conservancy project regulation influence.

The invention provides a mountain area small watershed mountain torrent disaster early warning method based on rain-water-sand change. The method comprises the following steps: selecting a siltable section from a siltable river reach of a target river reach; calculating the disaster water level of the siltable section behind the designed flood sand-carrying silt bed under different designed floodflow conditions, and drawing a water level flow relation curve; according to the early warning water level of the siltable section, obtaining the flow corresponding to the early warning water level ofthe siltable section from the water level flow relation curve, wherein the flow is the early warning flow, and the critical rainfall is reversely deduced according to the early warning flow; after heavy rainfall occurs at the upstream of the target river reach, monitoring the rainfall information in real time, and when the rainfall reaches or exceeds the critical rainfall, sending out mountain torrent disaster early warning. According to the method, the coupling effect of sediment and flood of the small watershed in the mountainous area is fully considered, the problem of water level increasecaused by sediment silt beds is considered when the early warning indexes are established, and more scientific basis and guidance can be provided for mountain torrent disaster prevention and controlof the small watershed in the mountainous area.

The invention discloses a design flood method based on an improved prior probability Bayesian model, and the method specifically comprises the steps: selecting a plurality of alternative lines, respectively calculating the comprehensive index value of each alternative line, building a Bayesian model according to the comprehensive index value, and calculating the design value of flood through the Bayesian model. According to the Bayesian model design flood method based on the improved priori probability, the precision of the Bayesian model is improved by improving the priori probability, and then the purpose of reducing the linear selection uncertainty influence is achieved, so that the design result precision is improved.

The invention discloses a design flood uncertainty analysis method based on hyper-quantitative flood time-varying characteristics. The method mainly comprises the following steps: constructing a super-quantitative flood series POT by adopting a flood peak sequence under a threshold value; establishing dynamic correlation between flood elements and physical influence factors by taking a basin waterand soil conservation area as a covariable, carrying out time-varying flood frequency analysis to deduce a design flood value in a specified recurrence period, and calculating an uncertainty influence interval of the human activity factors on the ultra-quantitative series design flood values in the specified recurrence period by combining an uncertainty analysis technology. According to the method, by constructing a flood ultra-quantitative series, the defect that the number of flood samples in a design flood calculation method based on an annual maximum AM series is small is overcome; by introducing the watershed water and soil conservation area, the reason causing the POT flood sequence time-varying property can be explained, the reliability of a time-varying property design flood result is improved, and support is provided for watershed flood control planning, scheduling and management.

The invention provides a most probable combination method of a design flood peak amount condition based on a Copula function. A joint distribution function of the flood peak amount and the flood amount in each period of the measured flood event constructed by the Copula function and a most probable combination value of the flood peak amount and the flood amount in each period of different flood control tasks calculated based on the derived multivariate condition most probable combination formula provide important references for designing the design flood design standards, and a new approach for analyzing the peak amount combination of design flood.

The invention belongs to the technical field of basin design flood derivation, and particularly relates to a non-consistent design flood calculation method considering influence of flood season dispersity. The non-consistent design flood calculation method comprises the following steps of: constructing a flood hyper-quantitative series POT; analyzing seasonal distribution characteristics of the flood in the year according to the over-quantitative series POT of the flood; constructing a POT flood probability distribution model by combining the flood flow magnitude sequence model and the flood intra-year occurrence frequency sequence model according to a flood seasonal test result; selecting the annual population Kt as a potential human activity indirect factor, and establishing a mathematical model between the Kt and statistical parameters of the flood flow magnitude sequence and the flood annual occurrence frequency sequence; and substituting the established statistical parameter mathematical model into the POT flood probability distribution model, and calculating a non-uniform design flood value according to a specified recurrence period of flood control requirements. According tothe non-consistent design flood calculation method, the defect that the flood calculation result designed based on the POT hyper-quantitative sequence is too large or too small is overcome to a certain extent, and support is provided for basin flood risk scheduling and management.

The invention belongs to the technical field of cascade reservoir flood period operation water level control, and particularly relates to a cascade reservoir flood period operation water level dynamiccontrol method based on time-varying design flood, which comprises the following steps of arranging sample data by taking date as abscissa and taking year as ordinate to carry out hyper-quantitativescreening; adopting two time-distortion parameters in a Poisson scale value process model with time-distortion parameters, wherein the two time-distortion parameters include the super-quantitative mean value and the super-quantitative generation intensity, and therefore deterministic factors and random factors in the actual inflow process of the reservoir are reflected; deducing the time-varying design flood of various design frequencies, and combining the date, the design frequency and the time-varying design flood value to form a time-varying warehousing flood recognition model to judge thedesign frequency and the line type of the warehousing flood; before entering the flood period, enabling the upstream reservoir to block and store the reservoir flood by lowering the flood period operation water level of the upstream reservoir to reduce the flood control pressure of the downstream reservoir, and enabling the downstream reservoir to increase the cascade reservoir power generation amount by exceeding the flood period limit water level operation.

The invention provides a hydraulics determination method for the utilization range and the flood control safety position of a compound beach land of a mountain river, which comprises the following steps: (1) calculating the corresponding flow when different values are taken for the relative water level under the condition of different effective water passing widths of a left beach land and a rightbeach land, and drawing the water level-flow relation graph of a typical section; (2) according to the designed flow of the target river reach and the designed flood control relative water level, calculating the maximum available width of the compound beach land in combination with the water level-flow relation graph; and (3) after determining the actual utilization width of the left beach land and the actual utilization width of the right beach land, calculating the corresponding flow when different values are taken for the relative water level, drawing the water level-flow relation curve, and determining the flood control safety relative water level in combination with the designed flow of the target river reach and the designed flood control relative water level, wherein the position located above the flood control safety relative water level is the flood control safety position.