CN106706475A - In-situ rainfall infiltration and runoff distribution measuring system and method - Google Patents

Abstract

The invention discloses an in-situ rainfall infiltration and runoff distribution measurement system and method, which belong to the technical fields of hydrology, environmental science and geology. The technical means adopted are an in-situ rainfall infiltration and runoff distribution measurement system, including The rainfall measurement system, infiltration measurement system and runoff measurement system set up in the test area, the rainfall measurement system includes a rain gauge fixed in the test area by means of a bracket; the infiltration measurement system includes moisture sensors laid at different depths of the soil by means of profile installation pipes The runoff measurement system includes a sump, a collecting ditch dug around the test area and connected to the sump, and a water level and water volume measuring device arranged at the interface between the collecting ditch and the sump. The advantages are as follows: easy to carry, quick installation, low cost, convenient and simple to use and maintain, easy to disassemble and recycle after use; avoid laboratory errors and environmental restrictions, and the results are more real and accurate; can be installed on different underlying surfaces above, the scope of application is wide.

Description

An in-situ rainfall infiltration and runoff distribution measurement system and method

technical field

The invention relates to the technical fields of hydrology, environmental science and geology, in particular to an in-situ rainfall infiltration and runoff distribution measurement system and method.

Background technique

Precipitation is an important manifestation of climate characteristics and an important hydrological and climatic element. Infiltration and runoff characteristics are important factors affecting soil water balance and ecosystem water cycle, and are an important part of ecosystem hydrology research. , the formation and evolution of the ecological environment and agricultural production play a decisive role. Hydrological processes such as rainfall, infiltration, and runoff are accompanied by changes in the natural environment and material migration, involving hydrology, environmental science, agriculture, and forestry. Accurately obtain the ratio of rainfall to infiltration, runoff, and The process is the basis for studying the hydrological process involved, the law of pollutant migration, soil erosion, and water resource redistribution.

At present, most of the rainfall research and observation equipment is concentrated in the artificial rainfall simulation system. The rainfall infiltration test device is usually designed and manufactured in the laboratory, and then the artificial rainfall is simulated, and the test soil is transported to the laboratory for re-use. Infiltration test measurements are carried out after backfilling. However, it is inevitable that these devices are in use. First of all, various physical parameters of the soil have changed greatly during the process of grabbing, transporting and repacking the soil, and it is difficult to maintain The original state of the soil. Second, the experimental environment cannot completely simulate the real environment, the size and scale are limited, and boundary effects affect the test results, resulting in large errors in the results and cannot faithfully reflect the real precipitation infiltration. Similarly, there are many methods for measuring soil water infiltration, such as single-ring infiltration meter, double-ring infiltration meter, tension infiltration meter, etc. However, these methods are all driven by a certain water head to measure the soil infiltration. On the one hand, due to the large difference between the above experimental methods and natural precipitation, on the other hand, the boundary effect caused by the damage to the soil surface during the installation of the instrument is prominent, resulting in the measured values of these methods and natural precipitation. There is a big difference in the infiltration situation. The traditional runoff distribution measurement system needs to build a runoff field. The runoff field is usually composed of side ridges, small areas surrounded by side ridges, collection tanks, runoff and sediment storage equipment, protective belts and drainage systems. The measurement system and method The high construction cost, large operation cost and difficult control of measurement error have brought a lot of inconvenience and difficulties to the traditional runoff distribution measurement. The patent of CN201620330519 discloses an in-situ soil rainfall infiltration measurement device, but the device has a complex structure and is inconvenient to use. More importantly, the setting of the rainfall box in the device, especially the bottom infiltration plate, greatly affects the The surface infiltration and runoff process of natural rainfall, and there is a large boundary influence in it, the measured soil infiltration data must be far from the real situation. The testing devices and methods that can measure the soil infiltration and runoff distribution in the rainfall process at the same time in the actual research are still lacking, and the research on hydrology and environmental science has been greatly restricted.

Contents of the invention

The object of the present invention is to provide an in-situ rainfall infiltration and runoff distribution measurement system and method to solve the existing problems of rainfall infiltration, runoff distribution measurement error, difficult and complicated measurement process, and high engineering cost. The measurement system was constructed on-site in the test area, and the measurement devices were scientifically installed to realize the real measurement of infiltration and runoff distribution under natural rainfall environment, with accurate results and strong reliability.

In order to achieve the above object, the present invention firstly provides an in-situ rainfall infiltration and runoff distribution measurement system, as the key of the present invention, the measurement system includes a rainfall measurement system, an infiltration measurement system and a runoff measurement system arranged in the test area system, the rainfall measurement system includes a rain gauge fixed on the test area by means of a bracket; the infiltration measurement system includes moisture sensors arranged at different depths of the soil by means of profile installation pipes; A collecting ditch connected with the sump and a water level and water volume measuring device arranged at the interface of the collecting ditch and the sump.

Preferably, the measurement system also includes a control system, the control system includes a collector connected to the rain gauge moisture sensor water level and water volume measuring device at the signal input end, an integrated processor connected to the signal output end of the collector, and The memory and the client are respectively connected to the signal output end of the comprehensive processor, and the measurement system forms an automatic measurement by means of a control system.

Preferably, the sump is rectangular, square, circular or elliptical, and the cross-sectional shape of the collecting ditch is an inverted isosceles triangle or rectangle.

Preferably, at least three moisture sensors are arranged at each depth of the soil.

Preferably, filter plates with a height of 5-10 cm are respectively added to the edges of the collecting ditch and/or the sump.

The present invention also provides an in-situ rainfall infiltration and runoff distribution measurement method, based on the above-mentioned in-situ rainfall infiltration and runoff distribution measurement system comprising a rainfall measurement system, an infiltration measurement system and a runoff measurement system, the method includes the following steps :

(1) Select the test area;

(2) Install in-situ rainfall infiltration and runoff distribution measurement system

2-a. Install the infiltration measurement system: each depth selected by the soil is used as the infiltration measurement unit, and each infiltration measurement unit is equipped with at least one moisture sensor;

2-b. Install the rainfall measurement system: fixedly install the rain gauge in the test area with the help of brackets;

2-c. Lay out the runoff measurement system: dig a rectangular collecting ditch along the periphery of the test area, excavate a sump connected with the collecting ditch, and finally install a water level and water volume measuring device at the interface between the collecting ditch and the sump;

(3) After the rainfall starts, collect the rainfall depth H collected by the rain gauge during the test period, the soil water content θ _n collected by the infiltration measurement system at the end of the test, the soil thickness H _n measured by each moisture sensor and its corresponding Controlled soil area S _n ,

(4) Calculation based on collected data

4-a. Calculate the rainfall I during the test period according to I=SH, where S is the area of the test area;

4-b. According to Q _total = Q ₁ + Q ₂ +...+Q _n , Q _n = S _n H _n (θ _n -θ _ns ), calculate the soil layer corresponding to the nth soil infiltration measurement unit during the test period Soil water change Q _n and total soil water change Q _total in the soil layer of the test area, where θ _ns is the initial soil water content;

4-c. Calculate the _total runoff R of the test area during the test period according to R _total = R _pool + R _ditch , the water flow change value of the sump R _pool = S _pool H _pool , and the water flow R ditch of the collection _ditch = Ditch B, _Ditch H, _Ditch L, where: _Pool S is the bottom area of the collecting tank, _Pool H is the change value of the water level height of the collecting tank during the test period, _Ditch B is the width of the collecting _ditch , and Ditch H is the inside of the collecting _ditch during the testing period Change value of water level height, L _ditch is the length of collecting ditch;

4-d. According to the water volume balance formula I=Qtotal+ _Rtotal + _Qcut , calculate the _intercepted water quantity _Qcut of the underlying surface.

Preferably, the method also includes a calibration step (5), collecting the flow count value R at the interface of the collecting ditch and the sump basin and comparing it with _{the calculated total runoff R, when (R total-R measurement ) / R total} If the absolute value is ≧10-30%, then return to step 4-b after processing the liquid level of the sump.

Preferably, the measurement system also includes a control system, the control system includes a collector connected to the rain gauge, moisture sensor, water level and water volume measuring device at the signal input end and a comprehensive processing system connected to the signal output end of the collector device and a memory and a client that are respectively connected to the signal output of the integrated processor, and the measurement system forms an automatic control measurement by means of a control system. In the step (3), after the rainfall begins, the control system receives the signal of the rain gauge and immediately To initialize the system, first collect the initial soil moisture content θns.

Preferably, the dug shape of the sump is rectangular, square, circular or elliptical.

The inventive method has the following advantages:

(1) The rainfall infiltration and runoff distribution measurement system provided by the present invention is portable, quick to install, low in cost, easy to use and maintain, easy to disassemble and recycle after use, and easy to reuse when needed next time;

(2) The rainfall infiltration and runoff distribution measurement system can be applied to monitoring and measurement under various surface and field conditions, avoiding laboratory errors and environmental restrictions, conforming to the principle of scientific experiment repeatability, and the results obtained are more real and accurate ;

(3) The system can be installed on different ground covers (grassland, bare land, crops, etc.) and underlying surfaces with different slopes according to the measurement object, and has a wide range of applications.

Description of drawings

Fig. 1 is a schematic plan layout diagram of the in-situ rainfall infiltration and runoff distribution measurement system of the present invention.

Fig. 2 is a schematic cross-sectional view of the installation of the infiltration measurement system of the present invention.

Fig. 3 is a schematic cross-sectional view of a water collection tank according to an embodiment of the present invention.

Fig. 4 is a schematic cross-sectional view of a collecting ditch according to an embodiment of the present invention.

In the figure, 1 represents the rain gauge, 2 represents the infiltration measurement system, 21 represents the moisture sensor, 22 represents the installation pipe, 23 represents the installation hole, 3 represents the runoff measurement system, 31 represents the collecting ditch, and 311 represents the edge filter plate of the collecting ditch , 312 represents the collecting ditch cover, 32 represents the sump, 321 represents the edge filter plate of the sump, 322 represents the sump cover, 33 represents the water level gauge, and 34 represents the flow meter.

detailed description

The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Example 1

This embodiment provides an in-situ rainfall infiltration and runoff distribution measurement system, see Figures 1-4, the measurement system includes a rainfall measurement system, an infiltration measurement system 2 and a runoff measurement system 3 arranged in the test area, the The rainfall measurement system includes a rain gauge 1 fixed in the test area by means of a bracket. The rain gauge 1 is used to measure rainfall and rain intensity. The installation of the bracket effectively prevents movement and damage. The installation bracket can be selected from engineering plastics, plexiglass or stainless steel, etc. A material whose size matches Rain Gauge 1. The infiltration measurement system 2 includes moisture sensors 21 arranged at different depths of the soil by means of cross-sectional installation pipes 22. Installation holes 23 for the moisture sensors 21 are reserved on the installation pipes 22. When in use, they are divided into multiple infiltration The measurement unit, the moisture sensor 21 at each depth is used to measure the soil moisture content of the corresponding infiltration measurement unit, in order to reduce the error, usually at least 3 moisture sensors 21 are arranged in the soil of each selected depth, and the average The value is standard, such as 0-5cm below the surface is the first infiltration measurement unit, 5-10cm below the surface is the second infiltration measurement unit, and at least three moisture sensors 21 are evenly distributed in each infiltration measurement unit. The runoff measurement system 3 includes a sump 32, a collection ditch 31, and a water level and water volume measuring device arranged in the collection ditch 31 and the sump 32. The collection ditch 31 is dug around the test area to form a closed area on the ground surface. Ditch 31 communicates with sump 32, and the surface runoff in the closed area of the surface formed by drainage ditch 31 merges into sump 32 during rainfall; A water gauge 33 is arranged in the sump 32 for measuring the water level (liquid level), and a flow meter 34 is preferably arranged at the interface of the sump 31 and the sump 32 for measuring the runoff flow into the sump 32.

Described sump 32 is rectangular, square, circular or oval, as shown in Figure 1 and Figure 3, sump 32 planes are set to above-mentioned shape, convenient construction on the one hand, easy to calculate when using on the one hand, accuracy is high; More preferably, the sump 32 is set to a round or elliptical shape with smooth edges, which greatly avoids the poor authenticity of water flow and calculation errors caused by uneven corners; the cross-sectional shape of the sump 31 is an inverted isosceles triangle (as shown in Figure 4 shown) or a rectangle.

The edge of the collecting ditch 31 and/or the sump 32 is respectively provided with a filter plate with a height of 5-10cm, referring to Fig. 3 and Fig. 4 respectively, the edge of the collecting ditch 31 is provided with a collecting ditch edge filter plate 311, The edge of the sump 32 is provided with a filter plate 321 on the edge of the sump. The material of the filter plate can be selected from materials with filtering functions such as non-woven fabrics and steel wire mesh. The setting of the filter plate effectively prevents debris such as silt from flowing with the runoff. of the jam.

Example 2

Compared with Example 1, the in-situ rainfall infiltration and runoff distribution measurement system in this example is provided with a cover above the collecting ditch 31 and the sump 32, as shown in Figures 3 and 4, the collecting The top of the ditch 31 is covered with a collecting ditch cover 312, and the top of the sump 32 is covered with a sump cover 322. The setting of the cover can minimize the rainwater error and ensure accurate and reliable measurement results.

Example 3

Different from Embodiment 1, the in-situ rainfall infiltration and runoff distribution measurement system in this embodiment also includes a control system, and the control system includes a signal input terminal that is connected to the rain gauge 1, the moisture sensor 21 and the water level respectively. A collector connected to the water volume measuring device, a comprehensive processor connected to the signal output end of the collector, and a memory and a client terminal respectively connected to the signal output end of the comprehensive processor. The measurement system forms an automatic measurement by means of a control system. In the specific use of this measurement system, the collector collects the data of the rain gauge 1, the moisture sensor 21, and the water level and water volume measuring device, and transmits the data to the integrated processor, and the integrated processor transmits the data to the memory after sorting and calculating , on the one hand, it is transmitted to the client through wireless/wired communication. Wherein, the integrated processor stores related collected data tables and calculation formulas. There are two trigger modes for the automatic measurement formed. The rain gauge 1 can be used to start the measurement when the data is collected, or the client can be used as a trigger to control the integrated processor to start the collection, storage and communication transmission.

Example 4

The present invention also provides an in-situ rainfall infiltration and runoff distribution measurement method based on the in-situ rainfall infiltration and runoff distribution measurement system comprising a rainfall measurement system, an infiltration measurement system and a runoff measurement system described in any of the above embodiments , the method includes the following steps:

(1) Select the test area; select a test area with a suitable area according to the requirements of the test and monitoring, usually the selected area ranges from 1-1000m ² .

(2) Install in-situ rainfall infiltration and runoff distribution measurement system

2-a. Install the infiltration measurement system: each depth selected by the soil is used as the infiltration measurement unit, each infiltration measurement unit is equipped with at least one moisture sensor, and the infiltration measurement system is based on the selected soil depths. As the infiltration measurement unit, three infiltration measurement units are set in the present embodiment, as shown in Figure 2, the first infiltration measurement unit is 0-5cm below the surface, and the moisture sensor 21 is installed at the middle height, that is, 2.5cm below the surface. 5-10cm below the surface is the second infiltration measurement unit, and 10-15cm below the surface is the third infiltration measurement unit. In each infiltration measurement unit, at least three moisture sensors 21 with the same level and height are evenly distributed, as shown in the figure As shown in 1, it can be seen that three uniformly distributed typical points selected by the infiltration measurement unit in this embodiment are installed with moisture sensors 21, and a total of 9 moisture sensors 21 are installed in this embodiment.

2-b. Install the rainfall measurement system: fixedly install the rain gauge 1 in the test area with the help of the bracket to measure the rainfall and rain intensity;

2-c, laying out the runoff measurement system: digging a rectangular collection ditch 31 and a sump 32 (as shown in Figure 1) along the periphery of the test area, and the sump 32 is dug in a shape of rectangle, square, circle or ellipse Shape, digging is set as rectangle (as shown in Fig. 1, Fig. 3) in the present embodiment, and collecting ditch 31 sections are isosceles triangle (as shown in Fig. 4) or rectangle, digging and setting rectangle in the present embodiment, collecting The ditch 31 communicates with the sump 32, and finally a water level gauge 33 and a flow meter 34 are set at the junction of the sump 31, the sump 32, and the junction of the sump 31 and the sump 32, as shown in Figure 1, Figure 3, and Figure 4 ;

(3) After the rainfall begins, collect the rainfall depth H collected by the rain gauge 1 during the test period and the soil water content θ _n of the nth infiltration measurement unit at the end of the test collected by the infiltration measurement system, and the water content measured by each moisture sensor 21 Soil layer thickness H _n and its corresponding controlled soil area s _n ,

(4) Calculation based on collected data

4-a. Calculate the rainfall I during the test period according to I=SH, where S is the area of the test area.

4-b. According to Q _total = Q ₁ + Q ₂ +...+Q _n , Q _n = S _n H _n (θ _n -θ _ns ), calculate the soil layer corresponding to the nth soil infiltration measurement unit during the test period The change of soil water quantity Q _n and the change of total soil water quantity Q _total in the soil layer of the test area, where θ _ns is the initial soil water content.

Specifically, in this embodiment, 3 infiltration units are arranged in total, and 9 moisture sensors 21 are installed, and the total depth of the test area _is 15 cm. The soil layer thickness H _n of the unit is multiplied by the corresponding controlled soil area _sn , and then multiplied by the average value of the water content changes measured by the three moisture sensors 21, that is, the soil water content θ _n of each infiltration measurement, the initial soil content The value of the water amount θ _ns is the average value measured by the three installed moisture sensors 21 , and the _final Qtotal=Q ₁ +Q ₂ +Q ₃ .

4-c, calculate the total runoff R of the test area in the test period according to R _total =R _pond +R _ditch R _total , the water flow change value of the sump 32 R _pond =S _pond H _pond , the water flow of the collection ditch 31 R _ditch =B _ditch H _ditch L _ditch , i.e. the volume of the water flow, in the formula: S _pond is the area at the bottom of the sump 32, the H _pond is the change value of the water level height at the beginning and end of the sump 32 during the test period recorded by the water gauge 33, and the B _ditch is the width of the collecting ditch 31, the H _ditch is the change value of the water level height in the collecting ditch 31 during the test period, and the L _ditch is the total length of the collecting ditch 31.

4-d. According to the water volume balance formula I=Qtotal+ _Rtotal + _Qcut , calculate the _intercepted water quantity _Qcut of the underlying surface.

Example 5

Different from Embodiment 4, the method of this embodiment also includes a calibration step. The method also includes a calibration step (5), collecting the total flow count value R _measured and calculated at the interface of the collecting ditch 31 and the sump 32. Runoff R _total comparison, when (R _total- R _measurement )/R _total absolute value≧10-30%, then after processing the water level of the sump 32, return to step 4-b, and process the sump 32 liquid level to the level The method is conventional stirring, etc.

Example 6

Different from Embodiment 4, the measurement system adopted in this method also includes a control system, and the control system includes a collector and a collector connected to the rain gauge 1, the moisture sensor 21, the water level and the water volume measuring device respectively at the signal input end. The comprehensive processor connected with the signal output end of the collector and the memory and the client terminal respectively connected with the signal output end of the comprehensive processor, the measurement system forms automatic control measurement by means of the control system, in the described step (3), after the rain starts , the control system receives the signal from the rain gauge 1 and immediately initializes the system. First, it collects the initial soil moisture content θ _ns , or manually controls the client to send the trigger signal to the integrated processor, and the integrated processor controls the collector to collect data. This setting guarantees The timeliness of the collected data is greatly improved, and the accuracy of the test is greatly improved.

Although the present invention has been described in detail with general descriptions and specific examples above, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. Therefore, the modifications or improvements made on the basis of not departing from the spirit of the present invention all belong to the protection scope of the present invention.

Claims (10)

1. a kind of rainfall infiltration in situ and runoff distribute measuring system, it is characterised in that the measuring system includes being arranged on survey Try the precipitation measuring system in region, infiltrate measuring system and footpath flow measuring system, the precipitation measuring system is included by branch Frame is fixed on the rainfall gauge of test zone；Infiltrating measuring system includes being laid in by section installing pipe the water of soil different depth Sub-sensor；Footpath flow measuring system includes collecting-tank, digs the afflux ditch on test zone periphery and with collecting-tank UNICOM and set Put water level and measure of water device in afflux ditch and collecting-tank.

2. measuring system according to claim 1, it is characterised in that also include control system, institute in the measuring system Stating control system includes the collection that signal input part is connected with rainfall gauge moisture transducer water level and measure of water device respectively Device and the collector signal output part comprehensive treatment device for connecting and the memory being connected respectively with comprehensive treatment device signal output part And client, the measuring system is by control system formation automatic measurement.

3. measuring system according to claim 1 and 2, it is characterised in that the collecting-tank is rectangle, square, circle Or it is oval, the cross sectional shape of afflux ditch is isosceles triangle or rectangle.

4. measuring system according to claim 1 and 2, it is characterised in that each depth of the moisture transducer in soil Degree at least arranges 3.

5. measuring system according to claim 1 and 2, it is characterised in that the edge of the afflux ditch and/or collecting-tank point It is the filter of 5-10cm not add height.

6. a kind of rainfall infiltration in situ and runoff distribution measuring method, based on including precipitation measuring system, infiltrate measuring system and Rainfall infiltration in situ and runoff the distribution measuring system of footpath flow measuring system, it is characterised in that the described method comprises the following steps：

(1) test zone is selected；

(2) rainfall infiltration in situ and runoff distribution measuring system are installed

Measuring system is infiltrated in 2-a, installation：Using the selected each depth of soil as measuring unit is infiltrated, each infiltrates measurement Unit installs at least one moisture transducer；

2-b, installation precipitation measuring system：By support rainfall gauge is fixedly mounted in test zone；

2-c, laying footpath flow measuring system：Rectangle afflux ditch is dug along test zone periphery, and excavates the collection with afflux ditch UNICOM Pond, finally sets water level and measure of water device in afflux ditch and collecting-tank interface；

(3) after rainfall starts, the rainfall depth H of rainfall gauge collection and the survey for infiltrating measuring system collection in testing time section are collected The soil moisture content θ that n-th infiltrates measuring unit at the end of examination_n, the measurement of each moisture transducer soil thickness H_nAnd its correspondence control The soil erosion S of system_n,

(4) calculated according to gathered data

4-a, according to I=SH calculate the testing time section rainfall I, in formula S be test zone area；

4-b, according to Q_Always=Q₁+Q₂+…+Q_n, Q_n=S_nH_n(θ_n-θ_ns), calculate testing time section soil and infiltrate measuring unit n-th Corresponding soil layer soil water amount changes Q_nChange Q with test zone soil layer holard_Always, θ in formula_nsFor initial soil is aqueous Amount；

4-c, according to R_Always=R_Pond+R_DitchCalculate the yielding flow R of test zone in testing time section_Always, the water-carrying capacity change of collecting-tank Value R_Pond=S_PondH_Pond, the water-carrying capacity R of afflux ditch_Ditch=B_DitchH_DitchL_Ditch, in formula：S_PondIt is collecting-tank floor space, H_PondFor testing time section is catchmented Pool water level height change value, B_DitchIt is afflux ditch width, H_DitchIt is height of water level changing value, L in testing time section afflux ditch_DitchIt is afflux Ditch length；

4-d, according to water balance formula I=Q_Always+R_Always+Q_Cut, calculate underlying surface retention water Q_Cut。

7. measuring method according to claim 6, it is characterised in that methods described also includes calibration steps (5), collection collection Stream ditch and collecting-tank interface flow count value R_SurveyWith the yielding flow R obtained by calculating_AlwaysCompare, as (R_Always-R_Survey)/R_AlwaysJue Dui Zhi≤ 10-30%, then after processing collecting-tank liquid level, return to step 4-b.

8. measuring method according to claim 6, it is characterised in that also include control system, institute in the measuring system State control system include signal input part respectively with adopting that rainfall gauge, moisture transducer, water level and measure of water device are connected Storage and the comprehensive treatment device being connected with collector signal output part and with depositing that comprehensive treatment device signal output part is connected respectively Reservoir, client, the measuring system form automatic control survey by control system, and in the step (3), rainfall starts Afterwards, control system receives udometric signal and carries out system initialization immediately, and initial soil moisture content θ is gathered first_ns。

9. measuring method according to claim 6, it is characterised in that the moisture transducer infiltrates measuring unit at each Installation site be uniform.

10. measuring method according to claim 6, it is characterised in that the collecting-tank digs and is shaped as rectangle, pros Shape, circle or ellipse.