Topological to Sequential Structure Transformation Method for Calculating Watershed Water Volume from Tree-like Water System Units

Abstract

The present invention discloses a method for converting the topological structure to the sequence structure in the calculation of water volume from dendritic water system units to river basins, including: Step 1, constructing the topological structure and sequence structure of complex dendritic water system basin units, wherein the sequence structure includes: unit sequence and inflow unit sequence; Step 2, based on the sequence structure, obtaining the primary inflow unit sequence and obtaining the first weighted water volume; Step 3, based on the sequence structure and the upper-level inflow unit sequence, obtaining the next-level inflow unit sequence; Step 4, based on the next-level inflow unit sequence, obtaining the second weighted water volume; Step 5, repeating Step 3 and Step 4 to obtain the total weighted water volume, and based on the total weighted water volume, obtaining the total river basin water volume, and repeating Step 2, 3 and 4 to obtain the total river basin water volume corresponding to all units. The present invention reduces the difficulty in constructing the flood simulation and prediction model for large river basins with complex water systems and improves the timeliness of flood simulation and real-time flood prediction.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrological simulation and forecasting in the water conservancy industry, and particularly relates to a method for converting the topological structure to a sequence structure for calculating the water volume from dendritic water system units to a basin. Background Art

[0002] Water volume includes but is not limited to hydrological processes such as runoff generation, precipitation, evaporation, etc. When using a lumped model for hydrological simulation and forecasting, for a large basin, it is usually necessary to divide into more units, calculate the runoff generation of each unit, and then calculate the runoff volume of the catchment / basin through the topological relationship between the units. For a relatively complex dendritic water system, the number of divided units is large, and the calculation of the runoff volume from the units to the basin exceeds the manual processing capacity, and a batch calculation method is urgently needed. That is, it is different from the runoff generation of regular grids by taking the average value Figure 1 (a), nor is it the point input-output relationship between the upstream and downstream of the river channel. The batch calculation of the runoff volume from the units to the basin needs to consider both the irregular topological structure between the units and the unit areas of different sizes, so it cannot be directly calculated through the regular grid and the topological relationship of the inflow and outflow. This severely limits the timeliness of the lumped hydrological model in the simulation and forecasting of complex basins.

[0003] The existing inventions regarding the calculation of basin water volume mostly focus on improving the confluence algorithm. There is no clear construction method for the existing topological relationship table of the upstream and downstream confluence relationship. The existing batch calculation method for the inflow and outflow of the river channel with a complex basin topological structure is only applicable to the batch processing of the inflow and outflow of linear river reaches, and is not applicable to the calculation of the water volume from the units closely related to the area to the basin. Therefore, it is urgent to solve the problem of batch calculation of the conversion of the water volume from the units of a complex dendritic water system basin to the basin. Summary of the Invention

[0004] To solve the above technical problems, the present invention proposes a method for converting the topological structure to a sequence structure for calculating the water volume from dendritic water system units to a basin, which can solve the problem of batch calculation of the conversion of the water volume from the units of a complex dendritic water system basin to the basin.

[0005] To achieve the above object, the present invention provides a method for converting the topological structure to a sequence structure for calculating the water volume from dendritic water system units to a basin, including:

[0006] Step 1, construct the topological structure and sequence structure of the units of a complex dendritic water system basin, wherein the sequence structure includes: unit sequence and inflow unit sequence;

[0007] Step 2, based on the sequence structure, obtain the primary inflow unit sequence and obtain the first weighted water volume;

[0008] Step 3, based on the sequence structure and the upper-level inflow unit sequence, obtain the next-level inflow unit sequence;

[0009] Step 4: Based on the sequence of the next-level inflow units, obtain the second weighted water volume;

[0010] Step 5: Repeat Step 3 and Step 4 to obtain the total weighted water volume, and based on the total weighted water volume, obtain the total basin water volume.

[0011] Optionally, in Step 1, constructing the topological structure of the complex tree-like water system basin unit includes:

[0012] Obtain the complex tree-like water system basin, divide the complex tree-like water system basin, and obtain several units;

[0013] Starting from the most downstream of the complex tree-like water system basin, encode the units using the method of going upstream against the current and increasing counterclockwise to obtain the encoded units;

[0014] Based on the encoded units, obtain the topological structure.

[0015] Optionally, in Step 1, constructing the sequence structure of the complex tree-like water system basin unit includes:

[0016] Arrange the encoded units in descending order to obtain the unit sequence;

[0017] Traverse the unit sequence, search for the codes of the units flowing into the downstream units, and obtain the inflow unit sequence.

[0018] Optionally, Step 2 includes:

[0019] Obtain the unit area sequence and the unit water volume sequence;

[0020] Based on the unit area sequence and the unit water volume sequence, traverse the primary inflow unit sequence to obtain the first weighted water volume.

[0021] Optionally, in Step 3, based on the sequence structure and the upper-level inflow unit sequence, obtaining the next-level inflow unit sequence includes:

[0022] Traverse the inflow unit sequence, item by item search for the positions of the same-coded objects as the upper-level inflow unit sequence, and search for the unit sequence objects at the same positions;

[0023] Based on the unit sequence objects, obtain the next-level inflow unit sequence.

[0024] Optionally, in Step 4, based on the next-level inflow unit sequence, obtaining the second weighted water volume includes:

[0025] Calculate the length of the next-level inflow unit sequence. When the length of the next-level inflow unit sequence is less than 1, stop the calculation and obtain the second weighted water volume of the next-level inflow unit sequence;

[0026] Otherwise, repeat step five until the length of the next-level inflow unit sequence is less than 1.

[0027] Optionally, in step five, obtaining the total basin water volume based on the total weighted water volume includes:

[0028] Based on step three and step four, obtain the total area of the inflow unit sequence;

[0029] Based on the total weighted water volume and the total area, obtain the total basin water volume;

[0030] Repeat step two, three, and four to obtain the total basin water volume corresponding to all units.

[0031] Compared with the prior art, the present invention has the following advantages and technical effects:

[0032] The present invention cleverly uses two sequences, the unit sequence and the inflow unit sequence, which are closely dependent and combined with each other, to realize the transformation from the topological structure to the sequence structure. The obtained sequence structure has the characteristics of high-cycle batch calculation. It avoids the miscalculation and omission caused by frequently identifying the water volume destination of the unit by the naked eye, and realizes the cumulative calculation of the batch inflow water volume. In addition, the unit sequence obtained by coding the units upstream and arranging them in descending order is to obtain a unique sequence structure for a specific basin. Different users can reproduce the same result, which will not vary from person to person, and the method is universal for different basins.

[0033] The second-layer nested loop of the present invention effectively solves the difficulty of querying the inflow object of the unit. The second-layer nested loop continuously updates the (i + 1)-th level inflow unit sequence. Suppose the length of the i-th level inflow unit sequence is 5, and the inflow unit of each unit is 6, then the number of units to be queried is 5 × 6 = 30. This is an exponentially increasing number of units. And it will be extremely difficult to judge by the naked eye for each model step length, and errors such as mistakes and omissions are very likely to occur. The second-layer nested loop of the present invention realizes the automated calculation of the water volume traceability of the unit, which not only has a short calculation time but also does not make mistakes.

[0034] The present invention can significantly improve the work efficiency of users and the certainty of the results, reduce the time for troubleshooting mistakes and failures, and reduce the model running time. If only judging the topological relationship between the unit and the basin by the naked eye for each model step length to calculate the basin water volume, for a basin with about 20 units, the calculation duration exceeds 10 minutes, and 60 steps will require 600 minutes, that is, 10 hours. The more units there are, the longer the duration will be, while the present invention can complete the calculation within 2 seconds. Therefore, the present invention can significantly improve the timeliness of flood simulation and real-time flood forecasting. Description of the Drawings

[0035] The accompanying drawings, which form a part of this application, are used to provide a further understanding of this application. The schematic embodiments of this application and their descriptions are used to explain this application and do not unduly limit this application. In the accompanying drawings:

[0036] Figure 1 is the flow chart of the difference in runoff calculation from the regular grid and irregular topological structure units to the basin in the embodiments of the present invention. Figure 1 (a) shows the unit situation considered when converting a certain regular grid unit to the water volume of the basin. Among them, the dark gray represents the unit to be considered for the water volume calculation of Basin 1 where 3 units flow in, and the light gray plus dark gray represents the unit to be considered for the water volume calculation of Basin 2 where 8 units flow in. Figure 1 (b) shows the unit situation considered when converting a certain simple example of a dendritic water system unit to the water volume of the basin. Among them, the dark gray represents the unit to be considered for the water volume calculation of Basin 1 where 3 units flow in, and the light gray plus dark gray represents the unit to be considered for the water volume calculation of Basin 2 where 7 units flow in.

[0037] Figure 2 is the flow chart of the method for converting the topology to the sequence structure in the calculation of the water volume from the dendritic water system units to the basin in the embodiments of the present invention.

[0038] Figure 3 is the process diagram for determining the correspondence between the unit coding and the sequence of the inflow units of the b8 unit corresponding to the basin level in the embodiments of the present invention. Figure 3 (a) shows the units corresponding to the 1st - level inflow unit sequence. Figure 3 (b) shows the units corresponding to the 2nd - level inflow unit sequence. Figure 3 (c) shows the units corresponding to the 3rd - level inflow unit sequence. Detailed implementation manners

[0039] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The following will refer to the accompanying drawings and combine with the embodiments to detail this application.

[0040] It should be noted that the steps shown in the flow chart of the accompanying drawings can be executed in a computer system such as a set of computer - executable instructions. And, although the logical order is shown in the flow chart, in some cases, the steps shown or described can be executed in a different order than here.

[0041] The present invention proposes an effective method for converting the topological structure to the sequence structure for calculating the water volume from multiple units of a large dendritic water system basin to the basin using a lumped hydrological model. The sequence structure is easy to process in batches, making it possible to process the water volume from units to the basin in batches, accelerating the calculation speed of runoff simulation and flood forecasting for large basins. And it reduces the difficulty of constructing a flood simulation and real - time flood forecasting model for large basins with complex water systems, improving the timeliness of flood simulation and real - time flood forecasting.

[0042] The present invention proposes a method for converting the topology to the sequence structure in the calculation of water volume from dendritic water system units to the basin, as Figure 2 shown, specifically including:

[0043] Step 1: Construct the topology structure and sequence structure of the complex dendritic water system basin units, where the sequence structure includes: unit sequence and inflow unit sequence;

[0044] Step 2: Based on the sequence structure, obtain the primary inflow unit sequence and obtain the first weighted water volume;

[0045] Step 3: Based on the sequence structure and the upper-level inflow unit sequence, obtain the next-level inflow unit sequence;

[0046] Step 4: Based on the next-level inflow unit sequence, obtain the second weighted water volume;

[0047] Step 5: Repeat Step 3 and Step 4 to obtain the total weighted water volume, and based on the total weighted water volume, obtain the total basin water volume.

[0048] Furthermore, in Step 1, constructing the topology structure of the complex dendritic water system basin units includes:

[0049] Obtain the complex dendritic water system basin, divide the complex dendritic water system basin, and obtain several units;

[0050] Starting from the most downstream of the complex dendritic water system basin, use the method of going upstream against the current and increasing counterclockwise to encode the units to obtain the encoded units;

[0051] Based on the encoded units, obtain the topology structure.

[0052] Specifically, unit encoding. The prerequisite for the implementation of the present invention is that the units have been divided, and the present invention does not involve the unit division method. Encode all units according to the flow direction of the dendritic water system. Starting from encoding the most downstream unit as 0, the encoding number increases gradually when advancing upstream until the source. When encountering a river bifurcation, the encoding numbers of the units after the bifurcation increase gradually in the counterclockwise direction. The units after the sub-bifurcations upstream of different bifurcations are numbered together in the counterclockwise direction. In this way, the encoding of all units is completed, that is, the digital construction of the topology structure of the units.

[0053] Furthermore, in Step 1, constructing the sequence structure of the complex dendritic water system basin units includes:

[0054] Arrange the encoded units in descending order to obtain the unit sequence;

[0055] Traverse the unit sequence, search for the encoding of the unit flowing into the downstream unit, and obtain the inflow unit sequence.

[0056] Specifically, construct the unit sequence. Each unit has its water volume, so it is necessary to construct the sequence of the units where the water volume is located. Arrange the numbers in the unit code from largest to smallest to form a descending unit sequence. The descending arrangement in this step and the principles of flowing upstream and increasing counterclockwise in Step 1 can ensure the uniqueness of the unit sequence, regardless of individual differences.

[0057] Construct the inflow unit sequence. For the unit sequence in the order from front to back, search for the codes / watershed outlets of the downstream units where the water volume flows into one by one according to the river flow direction to form the inflow unit sequence. Because it is a dendritic water system watershed, the number of units flowing from any unit is exactly one, so the length of the inflow unit sequence is equal to the length of the unit sequence. In this way, the topological structure is transformed into a sequence structure. The sequence structure includes the unit sequence and the inflow unit sequence. This sequence structure contains the same sufficient topological information as the topological structure and can be processed in batches without the need to repeatedly judge the upstream and downstream relationships by the naked eye.

[0058] Further, Step 2 includes:

[0059] Obtain the unit area sequence and the unit water volume sequence;

[0060] Based on the unit area sequence and the unit water volume sequence, traverse the primary inflow unit sequence to obtain the first weighted water volume.

[0061] Specifically, prepare for batch calculation. For a specific period of model calculation, the premise of this step is that the unit water volume and the unit area are default to have been obtained. Therefore, construct the unit area sequence and the unit water volume sequence according to the unit sequence order and the corresponding unit area and water volume. Traverse the unit sequence. For a specific unit sequence object, the object itself is used as the primary inflow unit sequence. First, multiply its area by the water volume to obtain the weighted water volume of this unit, and then calculate the water volume of all units flowing into this unit one by one to obtain the water volume of each unit corresponding to the watershed / catchment area.

[0062] Further, in Step 3, based on the sequence structure and the upper-level inflow unit sequence, obtaining the lower-level inflow unit sequence includes:

[0063] Traverse the inflow unit sequence, search for the positions of the objects with the same code as the upper-level inflow unit sequence item by item, and search for the unit sequence objects at the same positions;

[0064] Based on the unit sequence object, obtain the lower-level inflow unit sequence.

[0065] Further, in Step 4, based on the lower-level inflow unit sequence, obtaining the second weighted water volume includes:

[0066] Calculate the length of the lower-level inflow unit sequence. When the length of the lower-level inflow unit sequence is less than 1, stop the calculation and obtain the second weighted water volume of the lower-level inflow unit sequence;

[0067] Otherwise, repeat step five until the length of the next-level inflow unit sequence is less than 1.

[0068] Further, in step five, obtaining the total basin water volume based on the total weighted water volume includes:

[0069] Based on steps three and four, obtain the total area of the inflow unit sequence;

[0070] Based on the total weighted water volume and the total area, obtain the total basin water volume.

[0071] Specifically, for the batch calculation of the water volume flowing into a unit, a single query is performed. For a certain unit, find the inflow units with the same code as this unit in the inflow unit sequence. The units in the unit sequence corresponding to these inflow units are the units flowing into these inflow units. Count their number, denoted as the secondary inflow unit sequence. Multiply the area and water volume of each of them one by one, and sum to obtain the total weighted water volume of the secondary inflow unit sequence. Separately sum the areas to obtain the total area of the secondary inflow unit sequence.

[0072] For the batch calculation of the water volume of a certain unit's basin, traverse the previous-level inflow unit sequence. For a certain unit, generate the next-level inflow unit sequence and its corresponding total weighted water volume according to the method in step three. Then return to the beginning of this step and repeat the processes of steps three and four until the n-level inflow unit sequence. If the length of this sequence is 0, then do not repeat the process of step three. Sum the total weighted water volumes of all levels of inflow unit sequences and divide by the sum of the total areas of all levels of inflow unit sequences to obtain all the inflow water volumes of this unit, that is, the water volume of the basin / catchment area.

[0073] For the batch calculation of all basin water volumes, repeat the processes of step two, step three, and step four until the water volumes of the basins / catchment areas corresponding to all units are obtained.

[0074] Embodiment

[0075] Take Figure 3 the basin in (a) as the specific implementation object. This implementation object conforms to the characteristics of a complex dendritic water system basin, has multiple branched rivers, and is not overly complex so as to increase the difficulty of understanding. Therefore, this implementation object has high representativeness. The selection of this object does not affect the application of the present invention in more complex basins and does not affect the generality of the present invention, achieving an effective combination of complexity and understandability. Denote the basin outlet as o, and the unit results of the basin division have been obtained in advance, as shown in Figure 3 (a).

[0076] S1: Unit coding. Start from the unit with the code b0 at the most downstream, as shown in Figure 3(as shown in (a)). Continuing to search upstream for the unit flowing into b0, it is found that there is only one unit flowing into the b0 unit, and the code of this unit is b1. Continuing to search upstream for the unit flowing into b1, it is found that there are 2 units flowing into b1. According to the counterclockwise increasing principle, these two units are sequentially coded as b2 and b3. Then, looking upstream at the b2 and b3 units, it is found that b3 has reached the source, and the number of units flowing into b3 is 0, while b2 has 2 inflowing units. Therefore, also based on the counterclockwise increasing principle, the 2 units upstream of b2 are respectively coded as b4 and b5. Then continue to search upstream along b4 and b5, and it is found that the number of units flowing into these 2 units is 2 each, totaling 4 units. Therefore, these 4 units are coded together in counterclockwise increasing order, and the result is b6, b7, b8, and b9. And so on, to obtain all the river section codes as Figure 3 (as shown in (a)).

[0077] S2: Unit sequence construction. Sort the units according to the code, in the order of decreasing numbers in the code, to obtain the unit sequence, which is shown in the second column sb(i) of Table 1. The structure of this sequence is unique, and different users can reproduce the same result without variation from person to person.

[0078] S3: Inflow unit sequence construction. Traverse each object in the unit sequence from front to back, and search for the downstream unit / outlet it flows to. Their numbers are correspondingly arranged to form the inflow unit sequence. The first object in the unit sequence sb(1) = b19. According to the basin topology, the unit that the water volume of b19 flows to is b15, and b15 is the first object in the inflow unit sequence. The second object in the unit sequence sb(2) = b18. According to the basin topology, the unit that the water volume of b18 flows to is b15, and b15 is the second object in the inflow unit sequence. The first and second objects in the inflow unit sequence are the same, indicating that there can be multiple repeated objects in the inflow unit sequence. And so on, to obtain all the inflow unit objects corresponding to the unit sequence objects, and form the inflow unit sequence, which is shown in the third column to(i) of Table 1. Among them, the 20th object in the unit sequence sb(20) = b0. According to the basin topology, b0 is the most downstream unit, and the unit that its water volume flows to is the basin outlet o, and o is the 20th object in the inflow unit sequence. The unit sequence and the inflow unit sequence together form the sequence structure of the basin. In the next step, only use the sequence structure for calculation without analyzing the topology structure anymore.

[0079] S4: Batch calculation preparation. For a certain time period of the model, the areas and water volumes of all units are known. According to the unit sequence object, the unit area and water volume are corresponded one by one to obtain the unit area sequence and the unit water volume sequence, as shown in column 4 a(i) and column 5 v(i) of Table 1. The lengths of the 4 sequences in Table 1 are equal. Traverse each object of sb(i), i = 1...20, and calculate the water volume of its corresponding basin. When i = 1, sb(1) = b19, multiply its corresponding area and water volume to get the weighted water volume of sb(1) as a(1)×v(1). At the same time, b19 is used as the 1st-level inflow unit sequence. Traverse the inflow unit sequence to find sb(1) = b19, and the result is none, that is, the length of the 2nd-level inflow unit sequence is 0, indicating that b19 is already the source and there is no unit flowing into b19. Then the basin water volume corresponding to unit b19 when i = 1 is a(1)×v(1)÷v(1) = a(1). In this embodiment, since the calculation is relatively simple when i < 12 and it is difficult to reflect the multi-level inflow unit sequence, so let i increase to i = 12 as a typical unit for calculation. sb(12) = b8, multiply its corresponding area and water volume to get the weighted water volume of sb(12) as a(12)×v(12). At the same time, b8 is used as the 1st-level inflow unit sequence, as shown in Figure 3 (a).

[0080] S5: Single query for batch calculation of the water volume flowing into this unit. Search for the 1st-level inflow unit sequence (b8) one by one in the inflow unit sequence, and there are 2 matching objects, and the corresponding serial numbers are 5 and 6. Then [sb(5), sb(6)] are the 2 units flowing into the 1st-level inflow unit sequence (b8). [sb(5), sb(6)] corresponds to [b15, b14], so [b15, b14] is the 2nd-level inflow unit sequence, as shown in Figure 3 (b).

[0081] S6: Batch calculation of the basin water volume of a certain unit. The length of the 2nd-level inflow unit sequence is 2 ≥ 1. Multiply and accumulate the areas and water volumes of the objects in the sequence to get the total weighted water volume of the 2nd-level inflow unit sequence as a(5)×v(5)+a(6)×v(6), and the total area of the 2nd-level inflow unit sequence is a(5)+a(6). Execute step S5 for the 2nd-level inflow unit sequence [b15, b14]. First, search for b15 in the inflow unit sequence, and there are 2 matching objects sb(1) and sb(2), corresponding to [b19, b18]. Then, search for b14 in the inflow unit sequence, and there are 2 matching objects sb(3) and sb(4), corresponding to [b17, b16]. Then [b19, b18] and [b17, b16] are merged to get [b19, b18, b17, b16], which is the 3rd-level inflow unit sequence with a length of 4 ≥ 1, as shown in Figure 3(c). Multiply the area of the objects in the sequence by the water volume and accumulate them. The total water volume of the weight of the 3-level inflow unit sequence is a(1)×v(1)+a(2)×v(2)+a(3)×v(3)+a(4)×v(4), and the total area of the 3-level inflow unit sequence is a(1)+a(2)+a(3)+a(4). Then perform step S5 on the 3-level inflow unit sequence [b19, b18, b17, b16]. First, search for b19 in the inflow unit sequence. The number of matching results is 0, indicating that b19 is already the source and there are no units flowing into b19. Similarly, the number of matching results for b18, b17, and b16 in the inflow unit sequence is also 0, indicating that b18, b17, and b16 are already the sources and there are no units flowing into these units. Then it is impossible to generate a 4-level inflow unit sequence, that is, the length of the 4-level inflow unit sequence is 0. Then step S5 is not repeated. That is, the search for the water volume of the basin corresponding to unit b8 with i = 12 is completed. Then the water volume of this basin is the sum of the total water volume weights of the 1st, 2nd, and 3rd-level inflow unit sequences:

[0082] a(12)×v(12)+a(5)×v(5)+a(6)×v(6)+a(1)×v(1)+a(2)×v(2)+a(3)×v(3)+a(4)×v(4) divided by the sum of the total areas of the 1st, 2nd, and 3rd-level inflow unit sequences a(12)+a(5)+a(6)+a(1)+a(2)+a(3)+a(4).

[0083] S7: Batch calculation of the water volume of all basins. Return to the second half of step S4. Increment i by 1 to i = 13, sb(13) = b7. Repeat the processes of S4, S5, and S6 to search for the 1st, 2nd... n-level inflow unit sequences of unit b7, accumulate the total water volume of its weights, and divide by the sum of its total areas to obtain the water volume of the corresponding basin when i = 13. Then increment i by 1, i = 14, and repeat the processes of S4, S5, and S6 to obtain the water volume of the corresponding basin when i = 14. And so on to calculate the water volume of the basins / catchments corresponding to all units.

[0084] In summary, through the establishment of the topological structure by the unit coding in steps S1 and S2, and the construction of the unit sequence and the inflow unit sequence in steps S2 and S3, the transformation from the basin runoff topological structure to the sequence structure is realized. Through steps S4, S5, S6, and S7, based on the transformed sequence structure and the double-layer nested loop, the batch calculation of the water volume from the unit to the basin is realized. For other time periods of model simulation and prediction, just repeat the execution in the order of S4 - S7, and there is no need to execute steps S1 - S3 again. In this way, the automatic batch calculation of the water volume from the unit to the basin for all time periods of the model is realized.

[0085] Table 1

[0086]

[0087]

[0088] The above are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A topological-to-sequence structure conversion method for calculating the water volume from dendritic water system units to a basin, characterized in that Including: Step 1: Construct the topological structure and sequence structure of the complex dendritic water system basin unit, where the sequence structure includes: unit sequence and inflow unit sequence; In the said Step 1, constructing the topological structure of the complex dendritic water system basin unit includes: Obtain the complex dendritic water system basin, divide the complex dendritic water system basin, and obtain a number of units; Starting from the most downstream of the complex dendritic water system basin, encode the units by the method of going upstream against the current and increasing counterclockwise to obtain encoded units; Based on the encoded units, obtain the topological structure; In the said Step 1, constructing the sequence structure of the complex dendritic water system basin unit includes: Arrange the encoded units in descending order to obtain the unit sequence; Traverse the unit sequence, search for the codes of the units flowing into the downstream units, and obtain the inflow unit sequence, that is, the sequence structure; Step 2: Based on the sequence structure, obtain the primary inflow unit sequence and obtain the first weighted water volume; The said Step 2 includes: Obtain the unit area sequence and the unit water volume sequence; Based on the unit area sequence and the unit water volume sequence, traverse the unit sequence, and each unit sequence object is the primary inflow unit sequence, and obtain the first weighted water volume; Step 3: Based on the sequence structure and the upper-level inflow unit sequence, obtain the lower-level inflow unit sequence; In the said Step 3, obtaining the lower-level inflow unit sequence based on the sequence structure and the upper-level inflow unit sequence includes: Traverse the inflow unit sequence, search item by item for the position of the object with the same code as the upper-level inflow unit sequence, and search for the unit sequence object at the same position; Based on the unit sequence object, obtain the lower-level inflow unit sequence; Step 4: Based on the lower-level inflow unit sequence, obtain the second weighted water volume; In the said Step 4, obtaining the second weighted water volume based on the lower-level inflow unit sequence includes: Calculate the length of the lower-level inflow unit sequence. When the length of the lower-level inflow unit sequence is less than 1, stop the calculation and obtain the second weighted water volume of the lower-level inflow unit sequence; Otherwise, repeat Step 3 until the length of the lower-level inflow unit sequence is less than 1; Step 5: Repeat the said Step 3 and Step 4 to obtain the total weighted water volume, and based on the total weighted water volume, obtain the total basin water volume.

2. The topological-to-sequence structure conversion method for calculating the water volume from the tree-shaped water system unit to the basin according to claim 1, characterized in that In the said Step 5, obtaining the total basin water volume based on the total weighted water volume includes: Based on the said Step 3 and Step 4, obtain the total area of the inflow unit sequence; Based on the total weighted water volume and the total area, obtain the total basin water volume; Repeat the said Step 2, 3 and 4 to obtain the basin water volumes corresponding to all units.

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