CN106779232B - Modeling prediction method for urban inland inundation - Google Patents

Abstract

A modeling and prediction method of urban waterlogging obtains the possibility of occurrence of urban waterlogging by means of modeling. According to the fact that urban waterlogging is due to the fact that the water removal in natural conditions is less than the precipitation, the combination of numbers and shapes is used to calculate the urban water removal and the precipitation respectively. Urban precipitation, using software to convert urban water removal and urban precipitation into urban water removal effect map and urban precipitation effect map, and superimpose again to obtain urban water accumulation effect map. This processing method reduces a lot of tedious data processing, and at the same time Taking into account the actual situation of urban landforms, the latest urban water removal situation can be obtained in time, which can be of great reference value. By analyzing the urban water accumulation effect map, the occurrence of urban waterlogging can be predicted in advance.

Description

A Modeling Prediction Method of Urban Waterlogging

technical field

The invention relates to the field of urban waterlogging modeling, in particular to a modeling prediction method for urban waterlogging.

Background technique

In recent years, many cities in my country have been frequently hit by heavy rains, causing serious urban waterlogging, and the phenomenon of "waterlogging will occur every rain, and paralysis when encountering waterlogging". The failure of communication and underground cables causes flooding of markets, warehouses, factories and people's property, and even personal casualties, causing social order chaos and panic; the factors that affect urban waterlogging include: vegetation coverage, terrain height and rainfall, usually Under certain circumstances, the lower the vegetation coverage, the lower the terrain, and the more rainfall, the greater the possibility of urban waterlogging.

However, there is still no good way to prevent urban waterlogging. After the occurrence of urban waterlogging, we can only increase the use of drainage stations and drainage trucks to speed up urban drainage. There is not enough time to take reasonable solutions to urban waterlogging. This consumes a lot of manpower and material resources.

SUMMARY OF THE INVENTION

1. technical problem to be solved

Aiming at the problem in the prior art that urban waterlogging cannot be prevented in time before the occurrence of urban waterlogging, the purpose of the present invention is to provide a modeling prediction method for urban waterlogging, so as to predict the occurrence of urban waterlogging in advance.

2. Technical solutions

In order to solve the above problems, the present invention adopts the following technical solutions.

A method for modeling and predicting urban waterlogging, comprising the following steps:

(1) Build a model. Through the urban water circulation system, a white-box test method is used to establish an urban waterlogging model. The model is as follows:

M=H-Q;

Among them: M is the urban water accumulation, which refers to the difference between the urban precipitation and the urban water removal;

H is the urban precipitation in a certain area per unit time;

Q is the amount of water removed from the city, which refers to the amount of water absorbed by the vegetation soil, the drainage pipe network system and the surface flow;

(2) Determine the time period for the occurrence of waterlogging, and query the peak period of the city's annual precipitation. During the peak period of the city's precipitation, the city has the highest probability of waterlogging;

(3) Determine the level of urban waterlogging, and set urban waterlogging into four levels: micro-risk, low-risk, medium-risk and high-risk, and each level determines the range of urban waterlogging depth;

(4) Calculation of urban precipitation, by calculating the daily average precipitation during the peak period of annual precipitation in the city to obtain the frequency, frequency and grade classification table of urban precipitation;

(5) Graphical representation of urban precipitation, taking the specific value of urban precipitation as the value in image processing, and superimposing the processed image to obtain the urban precipitation effect map;

(6) Calculation of urban water removal, obtain the urban topographic map and urban vegetation coverage map, and perform grayscale processing on the pictures. After the grayscale processing, the urban topographic map and the urban vegetation coverage map are superimposed and fitted to obtain the urban water removal effect. Figure, superimpose the urban precipitation effect map and the urban water removal effect map to obtain the urban water accumulation effect map;

(7) Determine the level of urban waterlogging, determine the grayscale value of waterlogging occurrence in a city, and compare the grayscale values of different places in the urban waterlogging effect map one by one to obtain the predicted value of waterlogging occurrence in different parts of the city. Corresponding to the urban waterlogging grade, the urban waterlogging grade is obtained; the possibility of urban waterlogging occurrence is obtained through the modeling method. According to the fact that the urban waterlogging is due to the natural situation, the water removal is less than the precipitation, and the combination of numbers and shapes is used to calculate the urban water removal and Urban precipitation, using software to convert urban water removal and urban precipitation into urban water removal effect map and urban precipitation effect map, and superimpose again to get urban water accumulation effect map. This processing method reduces a lot of tedious data processing, and at the same time Taking into account the actual situation of urban landforms, the latest urban water removal situation can be obtained in time, which can be of great reference value. By analyzing the urban water accumulation effect map, the occurrence of urban waterlogging can be predicted in advance.

Preferably, in the step (6), the urban water removal amount includes the urban vegetation coverage rate, the drainage pipe network and the surface flow rate, and the urban vegetation coverage rate, the drainage pipe network and the surface flow rate respectively correspond to the urban vegetation coverage map, no, The urban topographic map, the urban vegetation coverage map and the urban topographic map are processed in grayscale respectively, and the different grayscale images obtained are superimposed to obtain the urban water removal effect map; combined with the use of modern drawing software, the urban vegetation coverage map and the urban topography are combined. The different grayscale images obtained by grayscale processing are superimposed to obtain the effect map of the total water removal amount. Through the pictures, you can simply understand the water removal conditions in different parts of the city. The larger the grayscale superposition in the picture, the darker the area, which means less vegetation. The lower the terrain, the greater the probability of water accumulation, and the smaller the grayscale overlay, that is, the whiter the place, which means that there is more vegetation. The higher the terrain, the lower the probability of water accumulation.

Preferably, in the step (2), the monthly average precipitation is obtained by querying the monthly precipitation of a certain area in the last 40 years, and the three months with the largest monthly average precipitation are selected as the precipitation peak period. This method can scientifically count the urban precipitation in recent years, making the data closer to the actual value in the future.

Preferably, in the step (4), by querying the daily precipitation during the peak period of annual precipitation in a certain area in the past 40 years, the daily average precipitation during the peak period of precipitation is obtained, and the frequency and frequency of urban precipitation are plotted. As well as a grade division table, the daily average precipitation is divided into four precipitation grades: light rain, moderate rain, heavy rain and heavy rain, and the precipitation amount, frequency and frequency of precipitation corresponding to different precipitation grades are counted, and the city is predicted in advance by the frequency estimation probability Precipitation, through tedious and rigorous data statistics to make the data more accurate.

Preferably, the four precipitation levels of light rain, moderate rain, heavy rain and heavy rain correspond to four different pictures, different precipitation amounts correspond to different grayscale values, and frequencies of different precipitation amounts correspond to transparency values, and the four different pictures are The images are superimposed to obtain the urban precipitation effect map, which reduces a lot of data processing, clearly and intuitively shows that the same precipitation occurs in all parts of the city during the prediction, and the water accumulation in various places after the precipitation in the city is known.

3. Beneficial effects

Compared with the prior art, the advantages of the present invention are:

(1) A modeling and prediction method of urban waterlogging The possibility of urban waterlogging is obtained by modeling. According to the fact that urban waterlogging is due to the natural water removal less than the precipitation, the combination of numbers and shapes is used to calculate the urban waterlogging respectively. Water removal and urban precipitation, using software to convert urban water removal and urban precipitation into urban water removal effect map and urban precipitation effect map, and superimpose again to get urban water accumulation effect map, this processing method reduces a lot of tedious data At the same time, considering the actual situation of urban landforms, the latest urban water removal situation can be obtained in time, which can be of great reference value. By analyzing the urban water accumulation effect map, the occurrence of urban waterlogging can be predicted in advance.

(2) In the present invention, combined with the use of modern drawing software, the different grayscale images obtained by grayscale processing of the urban vegetation coverage map and the urban topography map are superimposed to obtain the effect map of the sum of water removal. The situation of local water removal, in the picture, the larger the grayscale superposition, the darker the place, the less vegetation, the higher the probability of water accumulation, the smaller the grayscale superposition, the whiter the place, the more vegetation and the higher the terrain. less likely.

(3) In the present invention, the peak period of urban precipitation is determined by collecting the monthly precipitation data in the last 40 years, and selecting the three months with the most precipitation. closer to the actual value in the future.

(4) In the present invention, a table is drawn according to the average daily precipitation during the precipitation peak period in the last 40 years, and the urban precipitation is predicted in advance by the frequency estimation probability, and the data is more accurate through tedious and rigorous data statistics.

(5) In the present invention, the urban precipitation is processed into an urban precipitation effect map through pictures, which reduces a large amount of data processing, and clearly and intuitively shows that all parts of the city are subject to the same precipitation at the time of prediction. water condition.

Description of drawings

FIG. 1 is a flow chart of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

Example:

Please refer to Figure 1, a modeling and prediction method of urban waterlogging, including the following steps:

A method for modeling and predicting urban waterlogging, comprising the following steps:

(1) Build a model. Through the urban water circulation system, a white-box test method is used to establish an urban waterlogging model. The model is as follows:

M=H-Q;

Among them: M is the urban water accumulation, which refers to the difference between the urban precipitation and the urban water removal;

H is the urban precipitation in a certain area per unit time;

Q is the amount of water removed from the city, which refers to the amount of water absorbed by the vegetation soil, the drainage pipe network system and the surface flow;

(2) Determine the time period of waterlogging occurrence, query the peak period of the city's annual precipitation, and the probability of waterlogging in the city during the peak period of the city's precipitation is the greatest. By querying the monthly precipitation in Hefei in the past 40 years, obtain the monthly average Precipitation, the three months with the largest monthly average precipitation are selected as the peak period of precipitation. In this way, the urban precipitation in recent years can be calculated scientifically, making the data closer to the actual value in the future;

(3) Determine the level of urban waterlogging, and set urban waterlogging into four levels: micro-risk, low-risk, medium-risk and high-risk, and each level determines the range of urban waterlogging depth;

(4) Calculation of urban precipitation, by calculating the daily average precipitation during the peak period of annual precipitation in the city, the frequency, frequency and grade classification table of urban precipitation can be obtained. Calculate the daily average precipitation during the peak period of precipitation, draw the frequency, frequency and grade division table of urban precipitation, and divide the different daily average precipitation into four types of precipitation: light rain, moderate rain, heavy rain and heavy rain Level, count the precipitation, precipitation frequency and precipitation frequency corresponding to different precipitation levels, predict the urban precipitation in advance by the frequency estimation probability, and make the data more accurate through tedious and rigorous data statistics;

(5) Graphical representation of urban precipitation, taking the specific value of urban precipitation as the value in the image processing, and superimposing the processed image to obtain the urban precipitation effect map; the four precipitation levels of light rain, moderate rain, heavy rain and heavy rain correspond to four different images. For pictures, use different precipitation to correspond to different grayscale values, and different precipitation frequencies to correspond to transparency values. In Photoshop software, select four pictures with grayscales of 62, 92, 102, and 222 to represent the probability of rainfall, and four different pictures The effect map of urban precipitation is obtained by superimposing, which reduces a lot of data processing, clearly and intuitively shows that all parts of the city are subject to the same amount of precipitation at the time of prediction, and understand the situation of water accumulation in various places after precipitation in the city;

(6) Calculation of urban water removal, obtain the urban topographic map and urban vegetation coverage map, and perform grayscale processing on the pictures. After the grayscale processing, the urban topographic map and the urban vegetation coverage map are superimposed and fitted to obtain the urban water removal effect. Figure, the processed pictures are superimposed to obtain the urban precipitation effect map, and the urban precipitation effect map and the urban water removal effect map are superimposed to obtain the urban water accumulation effect map; the urban water removal amount includes the urban vegetation coverage, drainage pipe network and surface flow, urban vegetation The coverage rate, drainage pipe network and surface flow correspond to the urban vegetation coverage map, none, and the urban topography map respectively. The urban vegetation coverage map and the urban topography map are respectively processed in grayscale, and the different grayscale maps obtained are superimposed to obtain the urban water removal. The renderings; the vegetation coverage map of Hefei City and the topographic map of Hefei City were intercepted from GoogleEarth and Letu software, and the two pictures were imported into Photoshop software for grayscale processing. A complete image is composed of red, green, and blue. The thumbnails of the red, green, and blue channels are all displayed in grayscale, and different grayscale levels are used to represent the proportion of "red, green, and blue" in the image. The pure white represents that the color light is the highest brightness here, and the brightness level is 255. The grayscale processing map of Hefei vegetation coverage and terrain is obtained. After processing, the two pictures are superimposed; in the process of superposition and fitting, first Use the topographic map after grayscale processing as the background layer, adjust the transparency to 100%, then put the grayscale-processed vegetation cover image on the top layer, adjust the transparency so that the contents of both layers can be seen at the same time, adjust manually, and adjust the coordinates to coincide. Align the alignment, adjust the transparency to 50% before merging, and control the filling of the two images the same; through the pictures, you can simply understand the water removal situation in different parts of the city. The larger the grayscale overlay in the picture, the darker the place. If the vegetation is less and the terrain is low, the probability of water accumulation is greater. The smaller the grayscale overlay, the whiter the place, which means that there is more vegetation and the terrain is high, and the probability of water accumulation is smaller.

(7) Determine the level of urban waterlogging, determine the grayscale value of waterlogging occurrence in a city, and compare the grayscale values of different places in the urban waterlogging effect map one by one to obtain the predicted value of waterlogging occurrence in different parts of the city. Corresponding to the urban waterlogging grade, the urban waterlogging grade is obtained; the possibility of urban waterlogging occurrence is obtained through the modeling method. According to the fact that the urban waterlogging is due to the natural situation, the water removal is less than the precipitation, and the combination of numbers and shapes is used to calculate the urban water removal and Urban precipitation, using software to convert urban water removal and urban precipitation into urban water removal effect map and urban precipitation effect map, and superimpose again to get urban water accumulation effect map. This processing method reduces a lot of tedious data processing, and at the same time Taking into account the actual situation of urban landforms, the latest urban water removal situation can be obtained in time, which can be of great reference value. By analyzing the urban water accumulation effect map, the occurrence of urban waterlogging can be predicted in advance.

Among them, in practical application, pay attention to:

(1) When calculating the urban water volume, other water volumes such as domestic sewage and evaporation are not considered;

(2) Upstream water will have a significant impact on a city's pipe network drainage system and surface flow, resulting in a deviation in the amount of urban water accumulation. Since Hefei City is not a city near the Yangtze River, upstream water is not considered;

(3) The present invention does not consider sacrificing local areas to preserve administrative measures in economically developed areas;

(4) The daily rainfall in the present invention is based on the 24-hour continuous rainfall.

The above description is only a preferred embodiment of the present invention, but the protection scope of the present invention is not limited to this. The equivalent replacement or change of the improved concept thereof shall be included within the protection scope of the present invention.

Claims (2)

1. A modeling prediction method for urban waterlogging is characterized by comprising the following steps:

(1) establishing a model, namely establishing an urban waterlogging model by using a white box test method through an urban water circulation system, wherein the model comprises the following steps:

M=H-Q；

wherein: m is the urban water accumulation, which is the difference between the urban precipitation and the urban water removal;

h is the urban precipitation in a certain area in unit time;

q is the urban water removal amount, which means the water amount of vegetation soil absorbing water and a drainage pipe network system and the surface flow;

(2) determining the time period of waterlogging occurrence, inquiring the peak time of annual rainfall of the city, and maximizing the probability of waterlogging occurrence in the city in the peak time of the annual rainfall of the city;

(3) determining urban waterlogging grades, and setting the urban waterlogging into four grades of micro-risk, low-risk, medium-risk and high-risk, wherein each grade determines the depth range of the urban waterlogging;

(4) calculating urban precipitation, and obtaining urban precipitation frequency, frequency and grade division tables by counting daily average precipitation during annual precipitation peak periods of cities; the daily average precipitation amount of a certain area in the last four decades of the year at the peak precipitation amount is obtained by inquiring the daily precipitation amount in the last four decades of the year at the peak precipitation amount, an urban precipitation amount frequency, frequency and level dividing table is drawn, different daily average precipitation amounts are divided into four precipitation levels of light rain, medium rain, heavy rain and heavy rain, and the precipitation amount, the precipitation frequency and the precipitation frequency corresponding to different precipitation levels are counted;

(5) the method comprises the following steps of (1) graphically representing urban precipitation, wherein specific numerical values of the urban precipitation are used as numerical values in picture processing, and the processed pictures are superposed to obtain an urban precipitation effect graph; the four precipitation levels of light rain, medium rain, heavy rain and heavy rain correspond to four different pictures, different precipitation amounts correspond to different gray values, the frequencies of the different precipitation amounts correspond to transparency values, and the four different pictures are superposed to obtain an urban precipitation effect graph;

(6) calculating urban dewatering quantity, wherein the urban dewatering quantity comprises urban vegetation coverage, a drainage pipe network and surface flow, the urban vegetation coverage, the drainage pipe network and the surface flow respectively correspond to an urban vegetation coverage map, a city relief map and an urban vegetation coverage map, acquiring the urban relief map and the urban vegetation coverage map, carrying out gray level processing on the pictures, carrying out superposition fitting on the gray level processed urban relief map and the urban vegetation coverage map to obtain an urban dewatering effect map, and superposing the urban dewatering effect map and the urban dewatering effect map to obtain an urban ponding effect map;

(7) determining the urban waterlogging grade, determining a gray value of urban waterlogging occurrence, comparing gray values of different places in an urban waterlogging effect map one by one to obtain waterlogging occurrence predicted values of different places in the city, and obtaining the urban waterlogging grade according to the waterlogging occurrence predicted value corresponding to the urban waterlogging grade.

2. The modeling and forecasting method for urban waterlogging according to claim 1, characterized in that: and (2) inquiring the rainfall of each month in the last forty years in a certain area to obtain the average rainfall of each month, and selecting the three months with the maximum average rainfall of each month as the peak period of the rainfall.

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