Flood analysis device, flood analysis method, and flood analysis program

Abstract

To provide a flood analysis device that can conveniently incorporate rice paddy dams as models in flood simulations using structural grids.SOLUTION: The flood analysis device for evaluating rainwater storage by rice paddy dams that drain into rivers via rice paddy drainage channels includes: a storage unit 140 for storing model data for a flood model using a structural grid for farmland where multiple rice paddy dams are distributed and a river model for the rivers, and a rice paddy dam model for the rice paddy dam, and a rice paddy drainage channel model for the rice paddy drainage channel; and an analysis processing unit 100 for performing a flood simulation to determine water depths in the rice paddy dams and the river on the basis of rainfall, on the basis of the flood model, the river model, the rice paddy dam model, and the rice paddy drainage channel model, where a rice paddy dam occupancy rate is set for each cell.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flood analysis device, a flood analysis method, and a flood analysis program for evaluating rainwater runoff suppression by a rice paddy dam. [Background technology]

[0002] A rice paddy dam is a rice paddy that has been constructed by installing a rice paddy dam device at the drainage outlet of the rice paddy to adjust the amount of water stored and temporarily store rainwater that falls on the paddy. This allows a wide area and many rice paddies to temporarily store rainwater and function as a flood control reservoir, preventing the rise in water levels in waterways and rivers downstream from the rice paddies and ultimately reducing flood damage downstream.

[0003] Patent Document 1 discloses a "paddy field water storage volume adjustment device" as a rice paddy dam device, and describes an example of a structure for controlling the amount of water stored in a rice paddy. Even if such a device is installed in one rice paddy, the amount of water stored is very small, and the effect of preventing flood damage downstream is small. In order for rice paddy dams to be effective in preventing flood damage, they need to be installed over a wide area and in many rice paddies.

[0004] Non-patent document 1 discloses that before actually constructing rice paddy dams in a wide range of rice fields and in a large number of rice fields, flood simulations are conducted to evaluate the extent to which the rice paddy dams can be effective in reducing flood damage in the area.

[0005] In detail, the rice paddy dam simulation in Non-Patent Document 1 consists of three modules: an inflow / outflow calculation module that calculates the outflow from each land use, a one-dimensional unsteady flow module that calculates the flow in the drainage channel, and a flood flow module that calculates the planar propagation of the flood flow.

[0006] Of these, the flood flow module uses "terrain-adaptive cells" that actively divide the grid according to land use and topography. Each cell is either a rice field, farmland, or urban area, and the grid is divided so that rice fields, farmland, and urban areas do not coexist within a single cell. This has succeeded in achieving both efficient calculations and maintaining accuracy. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-120510 [Non-patent literature]

[0008] [Non-Patent Document 1] Natsuki Yoshikawa, Susumu Miyazu, Hiroyasu Yasuda, Shinichi Misawa, Development of an Inland Flooding Analysis Model for Low-lying Agricultural Areas, Journal of the Japan Society of Civil Engineers, Vol. 67, No. 4, 2011. Summary of the Invention [Problem to be solved by the invention]

[0009] In practical simulations, structured grids of a fixed size are often used. For example, when creating a map of expected flood areas for a first-class river, a structured grid with a side size of approximately 25m (1 / 3200 degrees in the longitude direction, 1 / 4800 degrees in the latitude direction) is used. Structured grids are efficient in that a mesh can be generated simply by specifying the mesh size and the calculations required for the simulation are short, and they are also transparent in that the mesh shape will be the same no matter who performs it.

[0010] In the simulation of rice paddy dams using "terrain-adaptive cells" in Non-Patent Document 1, the burden of creating "terrain-adaptive cells" is high, so it is preferable to simulate rice paddy dams using a structured grid. However, when using a structured grid, it is inevitable that rice paddies, farmland, urban areas, etc. will coexist within a single cell. If a single grid is represented by a single land use (rice paddies, farmland, urban areas), the area of ​​the rice paddies will be inaccurate. This will reduce the accuracy of the evaluation of rice paddy dams.

[0011] The present invention has been made in consideration of the above-mentioned problem, and aims to provide a flood analysis device, a flood analysis method, and a flood analysis program that can easily incorporate a rice paddy dam as a model in a flood simulation using a structural grid. [Means for solving the problem]

[0012] In order to solve the above problems, the flood analysis device of the present invention is a flood analysis device that evaluates rainwater storage by rice paddy dams that drain into rivers via rice paddy drainage channels, and is equipped with a memory unit that stores model data for a flood model using a structural grid for agricultural land where multiple rice paddy dams are distributed, a river model for the river, a rice paddy dam model for the rice paddy dams, and a rice paddy drainage channel model for the rice paddy drainage channels, and an analysis processing unit that performs a flood simulation to determine the water depth of the rice paddy dam and river from rainfall based on the flood model, the river model, the rice paddy dam model, and the rice paddy drainage channel model, in which the rice paddy dam occupancy rate of the rice paddy dams in each cell is set. [Effects of the Invention]

[0013] According to the present invention, even if a rice paddy dam is mixed with other rice paddy dams or non-rice paddy dams within a single cell of a flood simulation using a structural grid, it is possible to evaluate the rice paddy dam with high accuracy. [Brief explanation of the drawings]

[0014] [Figure 1]FIG. 1 is a diagram illustrating a configuration of a flood analysis device according to an embodiment of the present invention. [Figure 2A] FIG. 10 is a diagram showing a flood model using a structured grid. [Figure 2B] This figure shows the rice paddy dam occupancy rate of cells in the flood model. [Figure 3] FIG. 10 is a diagram showing the data structure of flood model data. [Figure 4] FIG. 2 is a diagram showing the data structure of cell data. [Figure 5] FIG. 10 is a diagram showing the data structure of rice field dam model data. [Figure 6] FIG. 10 is a diagram showing the data structure of rice field drainage channel model data. [Figure 7] FIG. 2 is a diagram showing the data structure of river model data. [Figure 8] 10 is a flowchart showing the overall processing of a flood simulation program. [Figure 9] 10 is a flowchart showing details of a flow analysis process of a flood model. [Figure 10] FIG. 10 is a diagram showing a GUI displayed by a flood simulation program. [Figure 11] FIG. 10 is a diagram showing a GUI during execution of a flood simulation program. [Figure 12] FIG. 10 is a sequence diagram showing the operation of the inundation analysis device. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of a flood analysis device according to this embodiment.

[0016] The flood analysis device of this embodiment is a computer comprising an analysis processing unit 100 that performs flood simulations using a structural grid, an input / output unit 110 that inputs operation information and outputs analysis results, and a memory unit 140 that stores various types of flood simulation information.

[0017] The input / output unit 110 is composed of an input unit for user operations, such as a keyboard 111 and a mouse 112, and a display 113 that displays analysis results and the like, allowing the flood results to be visually confirmed.

[0018] The analysis processing unit 100 includes a CPU (Central Processing Unit) 130 and a memory 120, and a flood simulation program 121 stored in a storage unit 140 is read into the memory 120. The CPU 130 then executes the flood simulation program 121 in the memory 120, thereby carrying out a flood simulation caused by a rice paddy dam in the analysis processing unit 100.

[0019] Furthermore, the CPU 130 controls the input / output unit 110 by the flood simulation program 121, and also refers to and saves various types of flood simulation information stored in the storage unit 140.

[0020] Here, the flood model for simulating flooding will be explained. Figure 2A shows a flood model using a structural grid for a flat area where rice paddy dams, drainage channels, and rivers are distributed. The flood model in Figure 2A is created before the simulation from farmland plot information (brush polygons) available in a geographic information system (GIS) or similar.

[0021] In the flood model of Figure 2A, rice fields of rice field dam type a are shown as polygons 211 filled with a dot pattern. Areas other than polygons 211 in Figure 2A are non-rice field areas, including rice field drainage channels and rivers. The flood model is defined as flood model data 141 consisting of grid definition information 210 and cell data 220, which will be described later.

[0022] For example, cell 213 of the flood model contains four rice fields, and rice fields do not occupy the entire area of ​​cell 213. Therefore, the area of ​​polygon 211 that occupies the interior of cell 213 is calculated and divided by the area of ​​the cell to calculate the rice field dam occupancy rate of rice field dam type a, which is set as flood model data 141 (cell data 220).

[0023] Figure 2B is a diagram showing the rice paddy dam occupancy rate of the cells in the flood model of Figure 2A. The rice paddy dam occupancy rate of cell 213 in Figure 2A is obtained as 0.75 (reference numeral 420).

[0024] Figures 2A and 2B show the case where the rice paddy dam is composed of rice paddy dams of rice paddy dam type a, but if the rice paddy dam is composed of multiple rice paddy dam types, the rice paddy dam occupancy rate is calculated for each rice paddy dam type and used as flood model data 141 (cell data 220).

[0025] Although details will be explained later, by introducing the rice paddy dam occupancy rate, the amount of precipitation in a cell is multiplied by the rice paddy dam occupancy rate to obtain the inflow amount of the rice paddy dam contained in the cell, and the outflow amount (storage amount) of the rice paddy dam is calculated. In this way, a flood simulation using a structural grid is carried out.

[0026] Next, the flood model data 141, river model data 142, rice field dam model data 143, and rice field drainage channel model data 144 stored in the storage unit 140 as the flood simulation information shown in FIG. 1 will be described in detail.

[0027] FIG. 3 is a diagram showing the data structure of the flood model data 141 in the flood model. The flood model data 141 is prepared for each flood simulation of a rice paddy dam, and is composed of grid definition information 210 of a structural grid and cell data 220 of each grid.

[0028] 2A, the grid definition information 210 is information about the two-dimensional structural grid of the flood model, and is information about cells obtained by dividing a predetermined two-dimensional area corresponding to the map data 145 (FIG. 1) in the storage unit 140 at regular intervals. The grid definition information 210 consists of a grid southwest edge coordinate (longitude) 311, a grid southwest edge coordinate (latitude) 312, a cell size (X direction) 313, a cell size (Y direction) 314, a number of cells (X direction) 315, and a number of cells (Y direction) 316.

[0029] Figure 3 shows the definition of a grid with specific values, where the east-west direction is the X axis (east is positive) and the north-south direction is the Y axis (north is positive), with the southwest end of the grid at 135 degrees east longitude and 35 degrees north latitude, with the cell size being approximately 25m in both the X and Y directions, divided into 1 / 3200 degrees in the longitude direction and 1 / 4800 degrees in the latitude direction, with 600 cells arranged in the X direction and 400 cells in the Y direction.

[0030] The grid definition information 210 includes a number of cell data 220 equal to the product of the number of cells in the X direction and the number of cells in the Y direction. FIG. 4 is a diagram showing the details of the data structure of the cell data 220 in FIG.

[0031] The cell data 220 indicates analytical information for each cell of the flood model, and consists of a cell ID 421, ground elevation 422, Manning's roughness coefficient 423, rice field dam data 424, non-rice field dam occupancy rate 425, water depth time series 426, flow velocity (X direction) time series 427, and flow velocity (Y direction) time series 428. The rice field dam data 424 consists of a set consisting of at least one name of rice field dam type 431, rice field dam occupancy rate 432, and rice field dam water depth time series 433.

[0032] The cell ID 421 is a unique value for each cell and identifies the cell's location, for example, the number of the cell from the southwest edge of the grid. The ground elevation 422 and Manning's roughness coefficient 423 are created in advance based on survey data and the like, and stored in the storage unit 140. Then, they are referred to when the cell data 220 is created. The water depth time series 426, the current velocity (X direction) time series 427, and the current velocity (Y direction) time series 428 are data showing the results of the flood simulation for each cell, and are stored as time-series array information.

[0033] The rice paddy dam data 424 is composed of a set of the name 431, rice paddy dam occupancy rate 432, and rice paddy dam water depth time series 433 for the number of types of rice paddy dams included in the cell. Here, the types of rice paddy dams are rice paddy dams that have the same rainwater runoff suppression effect per rice paddy area. As disclosed in the aforementioned Patent Document 1, the rainwater storage effect differs depending on the presence or absence of rice paddy dam equipment and the type of equipment. For example, a rice paddy dam equipped with a certain rice paddy dam equipment can be classified as rice paddy dam type a, a rice paddy dam equipped with another rice paddy dam equipment can be classified as rice paddy dam type b, and a rice paddy without a rice paddy dam equipment can be classified as rice paddy dam type c.

[0034] The name 431 of the rice field dam data 424 is a name that identifies the type of rice field dam. The rice paddy dam occupancy rate 432 of the rice paddy dam data 424 indicates the occupancy rate of the rice paddy dam specified by the name 431 in the cell. The name 431 and the rice field dam occupancy rate 432 are stored when the grid definition information 210 of the flood model is created based on the map data 145 .

[0035] The rice paddy dam water depth time series 433 of the rice paddy dam data 424 is data showing the results of a flood simulation of the rice paddy dam identified by the cell name 431, and is stored as time-series array information.

[0036] The non-rice field dam occupancy rate 425 indicates the proportion of the area other than rice fields in the cell. The sum of the non-rice field dam occupancy rate 425 and the rice field dam occupancy rate 432 is 1.

[0037] 5 is a diagram showing the data structure of the rice paddy dam model data 143. The rice paddy dam model data 143 is composed of a set of data for each type of rice paddy dam that is the target of a flood simulation by the flood analysis device, which set includes the name 501 of the rice paddy dam, the drainage capacity 502, the initial water depth 503, and the maximum water depth 504. In other words, the rice paddy dam model data 143 has the same number of data sets for the name 501 of the rice paddy dam, the drainage capacity 502, the initial water depth 503, and the maximum water depth 504 as the number of types of rice paddy dam.

[0038] The name of the rice paddy dam 501 is a name for identifying the rice paddy dam, and a different name is given to each type of rice paddy dam. Drainage capacity 502 defines the drainage amount as a function of the amount of change in water depth per unit time relative to the rice paddy dam water depth. For example, as shown in the table of drainage capacity 502 in Figure 5, when the rice paddy dam water depth is 0.1 m, the drainage amount is 10 mm / h.

[0039] The initial water depth 503 is the water depth of the rice paddy dam at the start of the flood simulation. The maximum water depth 504 is the height from the rice field ground surface to the ridge, and is the rice field dam water depth beyond which overflow will occur. As a result, the rice field dam water depth will not exceed the maximum water depth 504.

[0040] As mentioned above, the flood analysis device uses the amount of change in water depth per unit time as the drainage capacity of a rice paddy dam. Also, when the water depth of a rice paddy dam exceeds its maximum depth, it overflows, so the drainage volume is equal to the amount of rainfall and can be expressed as the amount of change in water depth per unit time. Therefore, the drainage volume of a rice paddy dam's drainage channel can be calculated by multiplying it by the area of ​​the rice paddy dam.

[0041] FIG. 6 is a diagram showing the data structure of the rice field drainage channel model data 144. The rice field drainage channel model data 144 is composed of a set of data for each rice field drainage channel that is the subject of flood simulation by the flood analysis device: rice field drainage channel name 601, river model name 602, river model cell ID (603), flood model cell ID (604), and drainage volume time series 605. In other words, the rice field drainage channel model data 144 has the same number of data sets as the number of rice field drainage channels that are the subject of flood simulation.

[0042] The name of the rice field drainage channel 601 is a name that identifies the rice field drainage channel. The name of the river model 602 is the name of the river model of the river into which the drainage water of the rice paddy drainage channel flows. The cell ID (603) of the river model is the cell ID of the river model corresponding to the position of the river to which the rice paddy drainage channel is connected.

[0043] The flood model cell ID (604) is the flood model cell ID corresponding to the route position of the rice paddy drainage channel in the flood model, and is stored as one or more pieces of array information. The drainage volume time series 605 is data showing the results of a flood simulation of the drainage volume of the rice paddy drainage channel, and is stored as time-series array information.

[0044] FIG. 7 is a diagram showing the data structure of the river model data 142. The river model data 142 is composed of a set of grid definition information 710 and cell data 720 for each river that is the subject of a flood simulation by the flood analysis device. In other words, the river model data 142 has the same number of data sets as the number of rivers that are the subject of a flood simulation.

[0045] The grid definition information 710 is information relating to the structural grid of a river, and is made up of a river name 711, river distance marker coordinates 712, and the number of cells 713. The river name 711 is a name that identifies the river.

[0046] The river distance marker coordinates 712 are data made up of multiple records, with each record consisting of a distance marker, left bank coordinate (longitude), left bank coordinate (latitude), right bank coordinate (longitude), and right bank coordinate (latitude). Note that a distance marker is the distance measured from the origin, with the downstream end of the river as the origin, along the left or right bank of the river (positive direction from downstream to upstream). The left bank and right bank refer to the left and right banks when the upstream of the river is seen as the rear and the downstream as the front.

[0047] The number of cells 713 is the number of cells in the structured grid river model. In Figure 7, for example, 200 mileposts are set every 0.2 km, and one cell is set for each milepost. Therefore, the number of cells 713 is 200.

[0048] The cell data 720 indicates analytical information for each cell of the river model, and consists of a set of data including a cell ID (721), a distance marker 722, a cross-sectional shape 723, a Manning's roughness coefficient 724, a water depth time series 725, and a flow velocity time series 726. The number of data sets in the cell data 720 is specified by the number of cells 713.

[0049] The cell ID (721) of the cell data 720 takes a unique value for each cell in the river model, and indicates the number of the cell from the most downstream cell. The distance marker 722 is the distance measured from the origin, which is the downstream end of the river of the cell, along the left or right bank of the river.

[0050] The cross-sectional shape 723 is an array consisting of the X and Y coordinates of the endpoints of the line segments that make up the cross section, with the line segment connecting the position of the distance marker 722 on the left bank and the position of the distance marker 722 on the right bank as the X axis (positive in the direction from the left bank to the right bank) and the vertical direction as the Y axis (positive upward).

[0051] The cell ID (721), milepost 722, cross-sectional shape 723, and Manning's roughness coefficient 724 are created in advance based on survey data and stored in the storage unit 140. They are then referenced when the cell data 720 is created.

[0052] The water depth time series 725 and the flow velocity time series 726 are data showing the results of the flood simulation for each cell of the river model, and are stored as time-series array information.

[0053] Next, the operation of the flood analysis device of the embodiment will be described. FIG. 8 is a flowchart showing the overall processing of the flood simulation program 121.

[0054] In step S81, the process starts from step S82 to step S810 repeatedly until the current time t becomes the end time T. At this time, the end time T, the flood model data 141, the river model data 142, the rice paddy dam model data 143, and the rice paddy drainage channel model data 144 are set in advance.

[0055] In step S82, the time is advanced by the time step width dt, and the flow analysis process of the flood model, which will be described later with reference to FIG. 9, is performed to calculate the water depth, flow velocity (X direction), and flow velocity (Y direction) for each cell at time t+dt.

[0056] In step S83, the process starts with repeating steps S84 to S85 for each of the plurality of rice paddy drainage channel models that are the subject of the flood simulation.

[0057] In step S84, the time is advanced by the time step width dt, a flow analysis of the rice paddy drainage channel model is performed, and the drainage volume is extracted from the flood model. In this flow analysis of the rice paddy drainage channel model, the rice paddy drainage channel is assumed to drain water according to the rice paddy water drainage capacity 502 (see Figure 5) for the rice paddy water depth calculated based on the cell water depth calculated in step S82. As a result, the rice paddy drainage volume QD from the current time t to time t + dt is obtained. In addition, the rice paddy dam water depth (rice paddy dam water depth time series 433) will decrease by the same amount.

[0058] In step S85, the rice field drainage volume QD calculated in step S84 is added to the cell indicated by the cell ID (603) of the river model of the river connected to the rice field drainage channel (the drainage from the rice field drainage channel flows into the river), and the drainage volume is added to the river model. At this time, the product of the rice field drainage volume QD and the area of ​​the rice field dam divided by the time step width dt is given as the lateral inflow to the river.

[0059] In step S86, when the processing from step S84 to step S85 is completed for each rice paddy drainage channel model, the process proceeds to step S87.

[0060] In step S87, time is advanced by the time step width dt, and flow analysis of the river model is performed using one-dimensional unsteady flow calculation to obtain the water depth and flow velocity for each cell at time t + dt. If there are multiple rivers being simulated for flooding, flow analysis is performed for each river model in step S87.

[0061] In step S88, the time step width dt is added to the current time t to update the current time t.

[0062] In step S89, the data obtained as a result of the flood simulation is stored as one of the time series data in the water depth time series 426 and rice field dam water depth time series 433 of the cell of the flood model data 141, the water depth time series 725 and flow velocity time series 726 of the river model data 142, and the discharge volume time series 605 of the rice field drainage channel model data 144.

[0063] In step S810, the data obtained as the result of the flood simulation is displayed on the display 113.

[0064] In step S811, when the current time t reaches the end time T, the processing of the flood simulation program 121 is terminated.

[0065] FIG. 9 is a flowchart showing the details of the flow analysis process of the flood model in step S82 of FIG. 8 in the flood simulation program 121.

[0066] In step S91, the process starts with repeating steps S92 to S910 for each cell of the flood model that is the target of the flood simulation using the structured grid.

[0067] In step S92, the process starts with repeating steps S93 to S96 for each rice field dam p of the rice field dam model included in the cell of the flood model.

[0068] In step S93, it is determined whether the rice paddy dam occupancy rate p.rate (rice paddy dam occupancy rate 432) of the rice paddy dam data 424 of the cell data 220 is greater than zero. If p.rate is greater than zero (True in S93), the process proceeds to step S94; if not (False in S93), the process proceeds to step S97.

[0069] 4, the rice paddy dam data 424 of the cell data 220 is configured with a set of data equal to the number of types of rice paddy dams included in the cell. Alternatively, in step S93, the rice paddy dam data 424 is configured with a set of data equal to the number of types of rice paddy dams included in the flood model, and the rice paddy dam occupancy rate 432 for rice paddy dams included in the cell is set to be greater than zero, and the rice paddy dam occupancy rate 432 for rice paddy dams not included in the cell is set to be zero.

[0070] In step S94, it is determined whether the rice paddy dam water depth p.depth (rice paddy dam water depth time series 433) of the cell data 220 is equal to or less than the rice paddy dam maximum water depth p.maxDepth (maximum water depth 504). If it is equal to or less (True in S94), proceed to step S95; if it is not equal to or less (False in S94), proceed to step S96.

[0071] In step S95, the rainfall amount precip is multiplied by the time step width dt and the result is added to the rice paddy dam water depth p.depth. Then, the process proceeds to step S97.

[0072] In step S96, the value obtained by multiplying the rainfall amount precip by the time step width dt and the rice paddy dam occupancy rate p.rate is added to the water depth cell.depth (water depth time series 426) of the cell of the flood model. Then, the process proceeds to step S97.

[0073] In step S97, when the processes from step S93 to step S96 are completed for each rice paddy dam p included in the cell, the process proceeds to step S98.

[0074] In step S98, the rainfall amount precip is multiplied by the time step width dt and the non-rice field dam occupancy rate cell.nonPRate (non-rice field dam occupancy rate 425) and added to the water depth cell.depth (water depth time series 426) of the cell in the flood model.

[0075] In step S99, the continuity equation for two-dimensional unsteady flow is solved.

[0076] In step S910, the equation of motion for the two-dimensional unsteady flow is solved.

[0077] In step S910, when the processing from step S92 to step S910 is completed for each cell of the flood model, the flow analysis processing of the flood model is terminated.

[0078] Next, the display of the flood simulation program 121 will be described. FIG. 10 is a diagram showing a GUI (Graphical User Interface) that the flood simulation program 121 displays on the display 113. As shown in FIG. A user of the flood analysis device checks the contents of the flood model data 141, river model data 142, rice paddy dam model data 143, and rice paddy drainage channel model data 144 through the GUI. The user also edits these data using the keyboard 111 and mouse 112 as necessary.

[0079] The GUI in FIG. 10 comprises a window 1000 that is made up of a project display section 1010, a property display section 1020, and a map display section 1030.

[0080] An overview of the project to be simulated is displayed in the project display section 1010. In Fig. 10, River X 1011 is set as the river, and Rice Paddy Dam A 1012, Rice Paddy Dam B 1013, Rice Paddy Dam C 1014, Rice Paddy Drainage Channel D 1015, and Rice Paddy Drainage Channel E 1016 are set as drainage pumping stations. The river name 711, rice paddy dam name 501, and rice paddy drainage channel name 601 are used to display these.

[0081] The property display section 1020 displays the properties of the item selected by the user. In Fig. 10, Rice Field Dam A 1012 is selected, and its properties are displayed. Rice field dam model data 143 is used as the properties. The user may edit each item of the properties using the keyboard 111, mouse 112, etc.

[0082] A map is displayed on the map display section 1030. Map data 145 is used for this display. The user may input the display range and scale of the map using the keyboard 111, mouse 112, etc. The display range of the map is changed by dragging the mouse 112. The scale of the map is changed by rotating the wheel of the mouse 112. An icon 1041 indicating the direction of north and a scale legend 1042 are displayed on the map.

[0083] In addition, in Figure 10, River X 1011 is displayed as area 1031, Rice paddy drainage channel D 1015 as polyline 1032, and Rice paddy drainage channel E 1016 as polyline 1033. The rice paddy occupancy rate of the selected Rice paddy dam A is displayed as area 1034. This area 1034 is made up of multiple flood model cells. The rice paddy dam cell is automatically connected to the nearest rice paddy drainage channel from that cell. Area 1034 is colored according to the rice paddy occupancy rate according to legend 1043.

[0084] If the user can confirm through this GUI that there are no problems with the contents, the user issues an instruction to execute a simulation to the flood simulation program 121. When the user selects Simulation from the menu 1001 and selects Start Simulation from the submenu that appears, the GUI transitions to the state shown in FIG.

[0085] FIG. 11 is a diagram showing the GUI during execution of the flood simulation program 121. The inundation model cells 1136 are filled in with colors corresponding to the inundation depth. The inundation depth indicated by the colors can be seen in the legend 1143. The inundation depth values ​​are based on the water depth time series 224 of the inundation model data 141. The flood depth displayed on the screen is updated successively until the current time 1144 in the flood simulation reaches the end time T. When the end time T arrives, the flood simulation ends.

[0086] FIG. 12 is a sequence diagram illustrating the operation of the flood analysis device according to the embodiment. In step S1201, the flood simulation program 121 reads the flood model data 141, the river model data 142, the rice field dam model data 143, the rice field drainage channel model data 144, and the map data 145 from the storage unit 140.

[0087] In step S1202, the flood simulation program 121 displays the window 1000 shown in FIG. 10 on the display 113 of the input / output unit 110 based on the data read in step S1201.

[0088] In step S1203, the flood simulation program 121 receives a user instruction to start a simulation via the input / output unit 110. The instruction is realized, for example, by the user performing a predetermined operation on the menu 1001 (FIG. 10).

[0089] In step S1204, the flood simulation program 121 starts the processing of the flood simulation that is executed until the current time t reaches the end time T, as explained in FIG. 8 and FIG.

[0090] In step S1205, the flood simulation program 121 stores the processing results of the flood simulation in the time-series information of the flood model data 141, the river model data 142, and the rice field drainage channel model data 144.

[0091] In step S1206, the flood simulation program 121 uses the input / output unit 110 to display the processing results of the flood simulation in a GUI.

[0092] In the above-mentioned flood simulation program 121, an example was explained in which the occupancy rate of rice paddy dams was introduced to perform calculations on a cell-by-cell basis in a structural grid flood model, but this is not limited to rice paddy dams; by introducing the occupancy rates of "rain gardens" and "permeable pavement roads" to the cells, simulations using structural grids are also possible.

[0093] The present invention is not limited to the above-described embodiments and includes various modifications. The above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. [Explanation of symbols]

[0094] 100 Analysis processing section 110 Input / output section 111 keyboard 112 Mouse 113 Display 120 memory 121 Flood Simulation Program 130 CPU 140 Storage section 141 Flood Model Data 142 River model data 143 Rice paddy dam model data 144 Rice paddy drainage channel model data 145 map data

Claims

1. A flood analysis device for evaluating rainwater storage by a rice paddy dam that drains water into a river via a rice paddy drainage channel, a storage unit that stores model data of a flood model using a structural grid for farmland in which a plurality of rice paddy dams are distributed, a river model for the river, a rice paddy dam model for the rice paddy dam, and a rice paddy drainage channel model for the rice paddy drainage channel; an analysis processing unit that performs a flood simulation to determine the water depth of the rice paddy dam and the river from the amount of rainfall based on the flood model, the river model, the rice paddy dam model, and the rice paddy drainage channel model, in which the rice paddy dam occupancy rate of the rice paddy dam in each cell is set; A flood analysis device comprising:

2. 2. The flood analysis device according to claim 1, The analysis processing unit The amount of water discharged from the rice paddy dam is calculated from the rice paddy water depth due to rainfall, and this is the amount of water discharged from the rice paddy drainage channel connected to the rice paddy dam. The drainage volume of the rice paddy drainage channel is added to a river model of the river to which the rice paddy drainage channel is connected, and the flow of the river model is analyzed to determine the water depth of the river. Flood analysis device.

3. 3. The flood analysis device according to claim 2, The analysis processing unit The drainage capacity of the rice paddy dam is defined as the amount of change in water depth per unit time relative to the rice paddy water depth, The drainage volume of the rice field drainage channel is calculated by multiplying the water depth change amount by the area of ​​the rice field dam. Flood analysis device.

4. A flood analysis method for a flood analysis device that evaluates rainwater storage by a rice paddy dam that drains into a river via a rice paddy drainage channel, comprising: In each cell of a flood model using a structural grid for a flat area where a plurality of rice paddy dams are distributed, the water depth of the rice paddy dams included in the cell is updated based on the amount of rainfall, and the water depth of the cell is updated based on the rice paddy dam occupancy rate of the rice paddy dams and the amount of rainfall; A step of calculating the drainage volume of the rice paddy dam from the rice paddy water depth of the rice paddy dam using a rice paddy drainage channel model of the rice paddy drainage channel, and setting the drainage volume as the drainage volume of the rice paddy drainage channel connected to the rice paddy dam; a step of calculating the water depth of the river by performing a river flow analysis by adding the drainage volume of the rice field drainage channel to a river model of the river to which the rice field drainage channel is connected; Flood analysis methods including:

5. A flood analysis program for a flood analysis device that evaluates rainwater storage by a rice paddy dam that drains into a river via a rice paddy drainage channel, On the computer, In each cell of a flood model using a structural grid for a flat area where a plurality of rice paddy dams are distributed, the water depth of the rice paddy dams included in the cell is updated based on the amount of rainfall, and the water depth of the cell is updated based on the occupancy rate of the rice paddy dams and the amount of rainfall; A procedure for calculating the drainage volume of a rice paddy dam from the rice paddy water depth of the rice paddy dam using a rice paddy drainage channel model of the rice paddy drainage channel, and setting the drainage volume as the drainage volume of the rice paddy drainage channel connected to the rice paddy dam; A procedure for calculating the water depth of a river by adding the drainage volume of the rice paddy drainage channel to a river model of the river to which the rice paddy drainage channel is connected and performing a river flow analysis; A flood analysis program that executes the above.

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