CN102314554A - Land-atmosphere coupling-based method and system for flood forecast of minor watersheds - Google Patents

Abstract

The invention provides a land-atmosphere coupling-based method and a system for flood forecast of minor watersheds, which are used for solving the problem of low accuracy for the flood forecast of the minor watersheds. The method comprises the following steps: setting model parameters; inputting initial data; judging a runoff-generation manner through analyzing the initial data, calculating surface runoff if the runoff-generating manner is infiltration excess runoff, and taking the surface runoff as simulation runoff; calculating the infiltration amount of soil if the runoff-generating manner is saturation excess runoff, and calculating base runoff and subsurface runoff by using the soil infiltration amount; calculating to obtain the simulation runoff according to the base runoff and the subsurface runoff when the soil is unsaturated; and further calculating the surface runoff and calculating to obtain the simulation runoff according to the base runoff, the subsurface runoff and the surface runoff when the soil is saturated. The land-atmosphere coupling-based method and the system provided by the invention are suitable for calculating the simulation runoff of the minor watersheds, and the calculating result is more accurate through the combination of theory and practice, thus the land-atmosphere coupling-based method and the system are suitable for short-term or ultra-short-term runoff forecast and have high forecast accuracy.

Description

A kind of small watershed flood forecasting method and system based on the coupling of land gas

Technical field

The present invention relates to hydrometeorology, particularly relate to a kind of small watershed flood forecasting method and system based on the coupling of land gas.

Background technology

Hydrologic forecast is according to early stage and information such as the current hydrology, meteorology, the qualitative or quantitative forecast that hydrologic regime in certain period in future is made.Hydrologic forecast is that hydrology is the importance of economy and community service, particularly disastrous hydrology phenomenon is given a forecast, and makes the forecast of short-term, medium and long term to fully utilizing Large Hydro-Junction, acts on very big.Flood forecasting is a part very important in the hydrologic forecast; Flood forecasting has a variety of methods; Wherein a kind of is to forecast flood through the prediction runoff, and described runoff is in hydrology cyclic process, the current that the different paths in longshore current territory are compiled to river, lake, marsh and ocean.

Flood forecasting that important field is a small watershed in the flood forecasting.Small watershed typically refers to and exports section with watershed divide and downstream river course below two, three grades of tributaries is that boundary's catchment area is at 100km ²The natural watershed of following relatively independent and sealing.Be often referred to area on the water conservancy less than 1000km ²Or the river course is the basin in county's genus scope basically.

Because the mountain area monitoring station of small watershed is few even do not have website, caused hydrologic data deficient, the artificial forecast of many employings.The manual work of small watershed flood forecast at present mainly is to adopt indirect method to inquire into; This method at first is that supposition rain flood is with frequently; Inquire into design flood by design storm, main method has rational formula method, 7 comprehensive instanteneous unit hydrograph methods, regional experience equation, historical flood investigation analytic approach etc.The rational formula method is claimed " rationalization formula " method again, is based on the method that ultimate principle that heavy rain forms flood is inquired into the design flood crest discharge.This kind method human factor is bigger, lacks of theoretical foundation, thereby cause the forecast precision of flood also lower.

Thereby, in the forecast of small watershed flood, lower at present to the forecast precision of flood, can not satisfy requirement to flood forecasting.

Summary of the invention

The present invention provides a kind of small watershed flood forecasting method and system based on the coupling of land gas, to solve the low problem of flood forecasting precision of small watershed.

In order to address the above problem, the invention discloses a kind of small watershed flood forecasting method based on the coupling of land gas, comprising:

Model parameter is set;

The input raw data;

Judge the runoff yield mode through analyzing raw data,, calculate rainwash if the runoff yield mode is the ultra runoff yield that oozes, with said rainwash as the simulation runoff;

If the runoff yield mode is a runoff yield under saturated storage, calculates milliosmolarity under the soil, and utilize milliosmolarity calculating base flow and interflow under the said soil;

When soil is unsaturated, calculate the simulation runoff according to said base flow and interflow;

When soil saturation, also calculate rainwash, and calculate the simulation runoff according to said base flow, interflow and rainwash.

Preferably, the said model parameter that is provided with comprises: underground water is set replenishes coefficient, maximumly ooze loss down, and the interflow coefficient that effluents, coefficient of groundwater runoff oozes loss index down, soil water storage capacity and hold back the storage volume parameter as model parameter.

Preferably, said input raw data comprises: the weather forecast rainfall amount of following certain period of input; The data that combine with measured discharge with virtual forecast, and the input meteorological factor is as raw data, said raw data comprises: the period rainfall amount; Vegetation is held back the savings amount; Potential evaporation ability, soil moisture, empirical parameter and underground water pondage.

Preferably, when the runoff yield mode is ultra when oozing runoff yield, said calculating rainwash comprises: calculate vegetation according to the following equation and hold back residual flow:

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value;

Said vegetation is held back residual flow as said rainwash.

Preferably, calculate milliosmolarity under the soil, comprising: infiltration rate and vegetation are held back and get minimum numerical value in the residual flow as milliosmolarity under the soil; Said infiltration rate does

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

Wherein, INF is an infiltration rate, and COEFF oozes loss under maximum, and S oozes loss index under being, SMS is a soil moisture, and SMSC is the soil water storage capacity;

Said vegetation is held back residual flow

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value.

Preferably, utilize milliosmolarity calculating interflow under the said soil, comprising: calculate interflow according to formula:

$\mathrm{SRUN}=\mathrm{SUB}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{RMO}$

Wherein, SRUN is an interflow, and SUB is the interflow coefficient that effluents, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil.

Preferably, utilize milliosmolarity calculating base flow under the said soil, comprising: calculate the soil water storage amount according to milliosmolarity under the soil; Judge whether the soil water storage amount reaches capacity; When the soil water storage amount reaches capacity, calculate the underground water pondage; Judge whether the underground water pondage reaches capacity; When the underground water pondage reaches capacity, calculate base flow.

Preferably, calculate the soil water storage amount according to milliosmolarity under the soil, comprising: soil moisture adds that the soil moisture magnitude of recruitment is as said soil water storage amount; Milliosmolarity deducts interflow under the soil, deducts underground water retaining magnitude of recruitment again as said soil moisture magnitude of recruitment.Said underground water retaining magnitude of recruitment does

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

Wherein, REC is the underground water pondage, and CRAK is that underground water replenishes coefficient, and U is an empirical parameter, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil, and SRUN is an interflow.

Preferably, calculate the underground water pondage, comprising: underground water retaining magnitude of recruitment adds that the underground water pondage of raw data input is as said underground water pondage.

Preferably, calculate base flow, comprising: coefficient of groundwater runoff multiply by the underground water pondage as said base flow.

Preferably, when soil saturation, calculate rainwash, comprising: vegetation is held back residual flow and deducts under the soil milliosmolarity as said rainwash.

Preferably, when soil was unsaturated, calculate the simulation runoff according to said base flow and interflow and comprise: base flow added that interflow is as said simulation runoff; When soil saturation, calculate the simulation runoff according to said base flow, interflow and rainwash and comprise: base flow adds interflow, adds rainwash as the simulation runoff.

The invention also discloses a kind of small watershed flood forecast system, comprising based on the coupling of land gas:

Load module is used to be provided with model parameter, and the input raw data;

Surpass and ooze the runoff yield module, be used to judge that the runoff yield mode is to surpass when oozing runoff yield, calculate rainwash, said rainwash will be as the simulation runoff;

The runoff yield under saturated storage module is used to judge when the runoff yield mode is runoff yield under saturated storage, calculates milliosmolarity under the soil, and utilizes milliosmolarity calculating base flow and interflow under the said soil;

Simulation runoff computing module is used for calculating the simulation runoff, if the runoff yield mode is to surpass to ooze runoff yield, obtains simulating runoff according to said rainwash; If the runoff yield mode is a runoff yield under saturated storage, when soil is unsaturated, calculate the simulation runoff according to said base flow and interflow, when soil saturation, also calculate rainwash, and calculate the simulation runoff according to said base flow, interflow and rainwash.

Preferably, said load module comprises: model parameter is provided with submodule; Be used to be provided with underground water and replenish coefficient, ooze loss under maximum, the interflow coefficient that effluents; Coefficient of groundwater runoff oozes down loss index, the soil water storage capacity with hold back the storage volume parameter as model parameter; Raw data input submodule is used to import the weather forecast rainfall amount of following certain period and the data that virtual forecast combines with measured discharge; And the input meteorological factor is as raw data; Said raw data comprises: period rainfall amount, vegetation are held back the savings amount, the potential evaporation ability; Soil moisture, empirical parameter and underground water pondage.

Preferably, the said ultra runoff yield module of oozing is calculated vegetation according to the following equation and is held back residual flow:

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value;

Saidly ultra ooze the runoff yield module said vegetation is held back residual flow as said rainwash.

Preferably, said runoff yield under saturated storage module comprises: milliosmolarity calculating sub module under the soil, be used to calculate milliosmolarity under the soil, and infiltration rate and vegetation are held back got minimum numerical value in the residual flow as milliosmolarity under the said soil; Said infiltration rate does

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

Wherein, INF is an infiltration rate, and COEFF oozes loss under maximum, and S oozes loss index under being, SMS is a soil moisture, and SMSC is the soil water storage capacity;

Said vegetation is held back residual flow

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value.

The interflow calculating sub module is used to calculate interflow, and interflow is calculated according to formula:

$\mathrm{SRUN}=\mathrm{SUB}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{RMO}$

Wherein, SRUN is an interflow, and SUB is the interflow coefficient that effluents, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil;

The base flow calculating sub module is used for calculating the soil water storage amount according to milliosmolarity under the soil; Judge whether the soil water storage amount reaches capacity; When the soil water storage amount reaches capacity, calculate the underground water pondage; Judge whether the underground water pondage reaches capacity; When the underground water pondage reaches capacity, calculate base flow.

Preferably, the base flow calculating sub module comprises: soil water storage amount computing unit, be used to calculate the soil water storage amount, and soil moisture adds that the soil moisture magnitude of recruitment is as said soil water storage amount; Milliosmolarity deducts interflow under the soil, deducts underground water retaining magnitude of recruitment again as said soil moisture magnitude of recruitment.

Said underground water retaining magnitude of recruitment does

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

Wherein, REC is the underground water pondage, and CRAK is that underground water replenishes coefficient, and U is an empirical parameter, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil, and SRUN is an interflow.

Underground water pondage computing unit is used to calculate the underground water pondage, and underground water retaining magnitude of recruitment adds that the underground water pondage of raw data input is as said underground water pondage;

The base flow computing unit is used to calculate base flow, and coefficient of groundwater runoff multiply by the underground water pondage as said base flow.

Preferably, said simulation runoff computing module calculates by following method: if the runoff yield mode is the ultra runoff yield that oozes, with said rainwash as the simulation runoff; If the runoff yield mode is a runoff yield under saturated storage, when soil was unsaturated, base flow added interflow as the simulation runoff, and when soil saturation, base flow adds interflow, adds rainwash as the simulation runoff.

Compared with prior art, the present invention includes following advantage:

At first, the present invention is applicable to that the simulation runoff of small watershed calculates, and through the combination of theory and practice, makes result of calculation more accurate, be fit to short-term or the Runoff Forecast of ultrashort phase, and forecast precision is higher.And the present invention imports the weather forecast rainfall amount; The data that combine with measured discharge with virtual forecast, and input temp, meteorological factors such as humidity and atmospheric pressure are as the raw data based on land gas coupling factor; Can obtain long leading time; The runoff that this method obtains can carry out flood forecasting, and combines with weather forecast, can realize the rolling forecast of weather, flood.

Secondly, the present invention is through computer realization, and when flash flood, computing velocity is very fast, but requirement of real time.

Description of drawings

Fig. 1 is the said a kind of small watershed flood forecasting method flow diagram based on the coupling of land gas of the embodiment of the invention;

Fig. 2 is the said a kind of small watershed flood forecasting method flow diagram based on the coupling of land gas of the preferred embodiment of the present invention;

Fig. 3 is the improved SIMHYD model structure figure of the said a kind of small watershed flood forecasting method based on land gas coupling of the embodiment of the invention;

Fig. 4 is the described a kind of small watershed flood forecast system structural drawing based on the coupling of land gas of the embodiment of the invention.

Embodiment

For make above-mentioned purpose of the present invention, feature and advantage can be more obviously understandable, below in conjunction with accompanying drawing and embodiment the present invention done further detailed explanation.

The present invention provides a kind of small watershed flood forecasting method based on land gas coupling, and the flow through runoff can carry out the prediction of flood, therefore can predict that precision is higher to the flood of small watershed.And the present invention, calculates soon when flash flood through computer realization, but requirement of real time.

With reference to Fig. 1, provided the said a kind of small watershed flood forecasting method flow diagram of the embodiment of the invention based on the coupling of land gas.

Step 101 is provided with model parameter;

The embodiment of the invention adopts hydrological model prediction runoff, at first carries out initialization, and model parameter is set.The parameter of model mainly contains 7, is respectively underground water and replenishes coefficient CRAK, the maximum loss COEFF that oozes down, and the interflow coefficient S UB that effluents, coefficient of groundwater runoff K oozes loss index S down, soil water storage capacity SMSC and hold back storage volume parameter I NSC.

Step 102, the input raw data;

The model parameter that input model needs in computation process.The weather forecast rainfall amount of following certain period of input and the data that virtual forecast combines with measured discharge, and the input meteorological factor is as raw data.

Step 103 is judged the runoff yield mode through analyzing raw data, if the runoff yield mode is the ultra runoff yield that oozes, calculates rainwash, with said rainwash as the simulation runoff;

Through analysis for raw data, judge the runoff yield mode, when the runoff yield mode is ultra when oozing runoff yield, can directly produce rainwash, the calculating rainwash, at this moment, rainwash is simulated runoff exactly.

Step 104 if the runoff yield mode is a runoff yield under saturated storage, is calculated milliosmolarity under the soil, and utilizes milliosmolarity calculating base flow and interflow under the said soil;

When the runoff yield mode is runoff yield under saturated storage, be seeped in the soil under the precipitation, calculate milliosmolarity under the soil, according to milliosmolarity under the described soil, calculate and try to achieve base flow and interflow.

Step 105 when soil is unsaturated, calculates the simulation runoff according to said base flow and interflow;

When soil was unsaturated, base flow added that interflow is as said simulation runoff.

Step 106 when soil saturation, is also calculated rainwash, and is calculated the simulation runoff according to said base flow, interflow and rainwash.

When soil saturation, can produce rainwash, calculate rainwash, therefore, base flow is added interflow, add rainwash as the simulation runoff.

In sum, at first, the present invention is applicable to that the simulation runoff of small watershed calculates, and through the combination of theory and practice, makes result of calculation more accurate, be fit to short-term or the Runoff Forecast of ultrashort phase, and forecast precision is higher.And the present invention imports the weather forecast rainfall amount; The data that combine with measured discharge with virtual forecast, and input temp, meteorological factors such as humidity and atmospheric pressure are as the raw data based on land gas coupling factor; Can obtain long leading time; The runoff that this method obtains can carry out flood forecasting, and combines with weather forecast, can realize the rolling forecast of weather, flood.

Secondly, the present invention is through computer realization, and when flash flood, computing velocity is very fast, but requirement of real time.

With reference to Fig. 2, provided the said a kind of small watershed flood forecasting method flow diagram of the preferred embodiment of the present invention based on the coupling of land gas.

Step 201 is provided with model parameter;

The preferred embodiment of the present invention adopts hydrological model prediction runoff, during calculating, at first will carry out initialization; Model parameter is set then, and the parameter of model mainly contains 7, is respectively underground water and replenishes coefficient CRAK; Maximum oozing down lost COEFF, the interflow coefficient S UB that effluents, coefficient of groundwater runoff K; Under ooze loss index S, soil water storage capacity SMSC with hold back storage volume parameter I NSC.

Step 202, the input raw data;

The weather forecast rainfall amount of following certain period of input and the data that virtual forecast combines with measured discharge, and import meteorological factor as raw data, said raw data comprises:

Period rainfall amount RAIN, vegetation is held back savings amount INS, potential evaporation ability PET, soil moisture SMS, empirical parameter U and underground water pondage GW.

Certainly, in addition, raw data can also comprise, historical rainfall amount, and upper reaches run-off, air pressure, data such as temperature can be selected the corresponding data of input according to the geographical situation of the different hydrology.

Step 203 is analyzed raw data, judges the runoff yield mode;

According to the period rainfall amount of input, analyze the influence of rainfall in early stage, judge the runoff yield mode.The runoff yield mode comprises, ultra runoff yield and the runoff yield under saturated storage of oozing.

Step 204, runoff yield mode are the ultra runoff yields that oozes, and calculate rainwash;

If the runoff yield mode is the ultra runoff yield that oozes, to calculate vegetation and hold back residual flow, it is exactly rainwash that vegetation is held back residual flow, and this moment, rainwash was exactly the simulation runoff of final output.

Said rainwash is meant through soil or ground cover and absorbs that part of natural rainfall that flows on the face of land that reaches remainder behind air evaporation.

Said vegetation is held back residual flow

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter.

When the calculating plant is held back residual flow, it is also conceivable that the influence of evaporation to rainfall amount, therefore also to calculate evaporation capacity.

Calculate evaporation capacity, comprise, calculate surface vegetation traps moisture evaporation capacity and soil water evaporation amount.Evaporation is that aqueous water is converted into vaporous water, escapes into the process of atmosphere.It is two piths of vaporization loss that the vegetation in basin is held back with soil evaporation.Comparatively speaking, the evaporation loss of soil is greater than vegetation and holds back loss amount, and the evaporation loss of soil has directly influenced the vaporization loss total amount in basin in computation process.The type difference of two kinds of evaporations causes both evaporation mechanism also to be not quite similar; The water yield evaporation of wherein being held back by plant is to evaporate according to the speed size of evaporative power, and soil evaporation then is to carry out according to the size of soil moisture content or residue evaporative power.The evaporation capacity computing formula of these two parts is as follows:

ET1＝MIN(INS，PET)

$\mathrm{ET}=\mathrm{MIN}(10\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{POT})$

POT＝PET-ET1

Wherein, ET1 is the evaporation of surface vegetation traps moisture; INS is that vegetation is held back the savings amount; PET is the potential evaporation ability; ET is a soil water evaporation; SMS is a soil moisture; SMSC is the soil water storage capacity; POT is the residue evaporative power.

Described vegetation is held back the savings amount and is meant that mainly precipitation drops to after the face of land, and the influence owing to surface vegetation, depression etc. has certain effect of damming to precipitation, and the water yield of holding back part just is called vegetation and holds back the savings amount.

Step 205, runoff yield mode are runoff yield under saturated storage, calculate milliosmolarity under the soil;

If the runoff yield mode is a runoff yield under saturated storage, be seeped in the soil under the precipitation, when soil is unsaturated, calculates vegetation and hold back milliosmolarity under residual flow and the soil; When soil saturation, can produce rainwash, will calculate vegetation and hold back milliosmolarity and rainwash under residual flow, the soil this moment.

Precipitation is seeped in the soil under falling earthward and understanding, and when under precipitation, oozing, soil constantly stores moisture, can produce interflow in the soil simultaneously.

The vegetation is here held back in residual flow computing method and the step 204 identical, therefore repeats no more.

Secondly, calculate milliosmolarity under the soil, milliosmolarity is the representative of model reaction basin physical mechanism under the soil, and precipitation drops to that soil certainly exists certain regulating action to precipitation on the ground.The calculating of milliosmolarity is part important in the computation process under the soil.Just calculate and must suppose between infiltration rate and the basin soil moisture content to have the negative power exponential relationship, only milliosmolarity can be calculated under soil under the prerequisite of this supposition.This supposition is simultaneously only just set up under the situation that satisfies the precipitation runoff relation.

The computing formula of milliosmolarity does under the soil

RMO＝MIN(INF，INR)

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

Wherein, RMO is a milliosmolarity under the soil, and INF is an infiltration rate, and INR is that vegetation is held back residual flow, and COEFF oozes loss under maximum, and S oozes loss index under being, SMS is a soil moisture, and SMSC is the soil water storage capacity.

Once more, calculate rainwash, said rainwash is meant through soil or ground cover and absorbs that part of natural rainfall that flows on the face of land that reaches remainder behind air evaporation.Computing formula does

IRUN＝INR-RMO

Wherein, IRUN is a rainwash, and INR is that vegetation is held back residual flow, and RMO is a milliosmolarity under the soil.

Step 206 is calculated interflow;

Precipitation is seeped in the soil under falling earthward and understanding, and when under precipitation, oozing, soil constantly stores moisture, can produce interflow in the soil simultaneously.Said interflow is meant that part of precipitation that is not seeped into ground water level down but enters the river course as undercurrent from this area.

Calculate interflow according to formula:

$\mathrm{SRUN}=\mathrm{SUB}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{RMO}$

Wherein, SRUN is an interflow, and SUB is the interflow coefficient that effluents, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil.

Step 207 is calculated the soil water storage amount;

Precipitation is through behind the surface retention, through under ooze and enter into soil, a part of water is stored in the soil, another part water oozes under continuing, and enters into base flow, exists the water yield in the soil just to be called the soil water storage amount.

The soil water storage amount in basin is calculated and is mainly comprised table vegetation moisture savings amount, soil moisture and three parts of underground water pondage.Each part connects each other when calculating, and the three successively permeates each other and replenishes.Generally speaking vegetation moisture savings amount with the place basin in vegetation coverage very big relation is arranged, when the savings amount of the intact then moisture of vegetation higher relatively.The geography of region, basin and precipitation event have directly influenced soil moisture, and long-time precipitation can make the humidity of soil higher if the basin is in humid region, when reaching certain saturation degree, can keep this fixed numbers.This variable quantity is a crucial intermediate change amount, determined the calculating of interflow, underground water pondage to a certain extent.

Soil moisture is the soil moisture that the soil moisture magnitude of recruitment adds the raw data input.

Soil moisture magnitude of recruitment computing formula is:

SMF＝RMO-SRUN-REC

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

The underground water magnitude of recruitment is represented with REC in the formula; The U empirical parameter; The soil moisture magnitude of recruitment is represented with SMF; Underground water replenishes coefficient and representes with CRAK.

Step 208 judges whether the underground water pondage reaches capacity, if do not reach capacity, then finishes to calculate, if reach capacity, then gets into step 209;

Judge whether the underground water pondage reaches capacity,, then finish to calculate if do not reach capacity; If reach capacity, be seeped into undergroundly under the precipitation, the underground moisture that constantly stores calculates the underground water pondage.

Step 209 is calculated the underground water pondage;

The state variable that becomes when the underground water pondage is one, a part becomes a run in depth part and becomes the underground water pondage when the water yield of interflow enters into deep phreatic water.The model computation process, the theoretical foundation of institute's basis all are principle of water balance.

The underground water pondage is the underground water pondage that underground water retaining magnitude of recruitment adds the raw data input.

In underground water retaining magnitude of recruitment computing formula such as the step 207, repeat no more here.

Step 210 judges whether the underground water pondage reaches capacity, if do not reach capacity, then finishes to calculate, if reach capacity, then gets into step 211;

Underground water stores moisture, judges whether the underground water pondage reaches capacity, if do not reach capacity, then finishes to calculate; If reach capacity, can produce base flow, base flow is a part basicly stable in the stream flow, mainly from the recharge of ground water, also comprises the supply from lake and glacier sometimes.

Step 211 is calculated base flow;

When the underground water pondage reaches capacity, can produce base flow, the computing formula of base flow does

BAS＝K×GW

Wherein, BAS is a base flow, and K is a coefficient of groundwater runoff, and GW is the underground water pondage.

Step 212 is calculated the simulation runoff.

The computing formula of simulation runoff does

RUNOFF＝IRUN+SRUN+BAS

Wherein, RUNOFF is the simulation runoff, and IRUN is a rainwash, and SRUN is an interflow, and BAS is a base flow.

If the runoff yield mode is oozed runoff yield for ultra, rainwash is simulated runoff exactly, and this moment, interflow and base flow were 0;

If the runoff yield mode is runoff yield under saturated storage, when soil saturation, base flow adds that interflow adds that rainwash simulates runoff exactly,

When soil was unsaturated, base flow added that interflow simulates runoff exactly, and this moment, rainwash was 0.

In sum, at first, the present invention is applicable to that the simulation runoff of small watershed calculates, and through the combination of theory and practice, makes result of calculation more accurate, be fit to short-term or the Runoff Forecast of ultrashort phase, and forecast precision is higher.And the present invention imports the weather forecast rainfall amount; The data that combine with measured discharge with virtual forecast, and input temp, meteorological factors such as humidity and atmospheric pressure are as the raw data based on land gas coupling factor; Can obtain long leading time; The runoff that this method obtains can carry out flood forecasting, and combines with weather forecast, can realize the rolling forecast of weather, flood.

Secondly, the present invention is through computer realization, and when flash flood, computing velocity is very fast, but requirement of real time.And, this model is packaged into service interface through the java language, implementation model is multiplexing.Certainly, this model can also use other programming languages, and should not be construed as is limitation of the present invention here.

The described hydrological model of the embodiment of the invention can adopt improved SIMHYD model, and the SIMHYD model is to HYDROLOG simplified models form, is the rainfall runoff model that calculates by the sky, estimates a day run-off through daily rainfall and regional potential evaporation ability.

The SIMHYD model is that the physical mechanism with the basin is the hydrological model that the basis is set up, and mainly is evaporation, rainfall and three kinds of hydrology data of runoff to be brought in the model calculate.Generally, this Model Calculation period can be a unit of account for day, the moon, carries out the midium or long term forecast.

The Runoff Forecast process of this model is fairly simple, and after precipitation fell earthward, if the surface vegetation rich, vegetation was stronger to the interception capacity of precipitation, and a large amount of precipitation can be held back by plant.Surface vegetation poor or do not have area, basin interception capacity that vegetation covers a little less than.Hold back remaining afterwards quantity of precipitation through oozing under the soil through plant, quantity of precipitation converts interflow, underground water and the holard into.When under rainfall amount surpasses basin soil, oozing ability, the part that surpasses directly produces rainwash.It is according to runoff yield under saturated storage and the ultra runoff yield calculating watershed rainwash that oozes that the process of confluxing is produced in the Model Calculation basin, adopts the linear estimation of soil moisture content interflow, calculates base flow by the linear reservoir principle of effluenting.At last, the river flow that rainwash, interflow and base flow linear superposition is obtained simulating.

Existing SIMHYD application of model precision is not high, is only applicable to medium-term and long-term footpath flow field simulation such as day, month, can't reach short-term or ultrashort phase runoff accuracy of simulation requirement.

With reference to Fig. 3, provided the improved SIMHYD model structure figure of the said a kind of small watershed flood forecasting method based on the coupling of land gas of the embodiment of the invention.

In embodiment of the present invention, the improvement of original SIMHYD model is mainly contained 3 points:

At first, the sample data of original model mainly comprises real-time quantity of precipitation, real-time traffic and three types of data of evaporation capacity.Because the ageing leading time to model prediction of these samples has certain constraint, therefore cause the leading time of model short, and then can not realize the demand of the long leading time of hydrologic forecast.

Improved model adopt weather forecast quantity of precipitation, and virtual forecasting runoff import as the model sample data; And be foundation with the meteorological condition of locality; Prolonged the leading time of model, obtained following river cross-section flood forecasting structure, the data support is provided for the leader does decision-making than long duration.

Secondly, when calculating infiltration rate, computing formula does in original model

$\mathrm{INF}=\mathrm{COEFF}\×e^{S\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

In improved model; Can obtain according to soil permeability test different temperatures situation water coefficient of dynamic viscosity the size of soil particle when etc. under to ooze influence bigger; Ooze loss index down and can reflect the two influence from the negative oozing down; So oozing loss under the adjustment on the basis of former formula, can be so that the infiltration rate after calculating tallies with the actual situation more.Through test of many times, constantly revise and ooze loss down and refer to corresponding coefficient, up to obtain one with actual soil moisture content along the curve that the depth direction variation conforms to, adopt following formula to calculate:

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

The result who obtains after the calculating is better, and soil moisture content is more tallied with the actual situation along the change curve of depth direction, and then makes the infiltration rate that calculates more accurate.After adopting many group experimental datas and measured data relatively, the result of calculation of improved model is greatly improved in precision than the result of calculation of master mould.

Once more, the computing formula of underground water retaining magnitude of recruitment does in original model

$\mathrm{REC}=\mathrm{CRAK}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×(\mathrm{RMO}-\mathrm{SRUN})$

In improved model, the computing formula of underground water retaining magnitude of recruitment does

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

Owing to can obtain better model output result through parameter optimization method; Therefore introduced empirical parameter U in the formula; Adopt ant group algorithm and particle cluster algorithm respectively parameter to be optimized in the computation process; Underground water retaining magnitude of recruitment can be regulated through custom parameter, more can reflect local soil water storage ability, has further improved the forecast precision of model.Wherein U is an empirical parameter.The variation range of U is (2,2.3), can carry out preferably as objective factor according to the hydrometeorological condition of locality.

SIMHYD model after the improvement is applicable to the footpath flow field simulation of short-term or ultrashort phase, and forecast precision is high, and leading time is long, is applicable to the small watershed flood forecasting.

The small watershed flood forecasting mainly is to adopt the experimental formula method to carry out at present; Artificial factor is big and forecast precision is very low; Leading time is short; And original SIMHYD model can not be applied directly in the small watershed flood forecasting, therefore carries out match through improved SIMHYD model and local conditions, makes improved SIMHYD model meet local hydrology round-robin Physical Mechanism after the calibration parameter; Solve the problem that the ultrashort phase prediction precision of small watershed heavy rain is low, leading time is short simultaneously, be fit to the mountain area flood forecasting.

Based on foregoing, the present invention also provides corresponding system embodiment.

With reference to Fig. 4, provided the described a kind of small watershed flood forecast system structural drawing of the embodiment of the invention based on the coupling of land gas.

The system of said prediction runoff can comprise load module 11, ultra runoff yield module 12, runoff yield under saturated storage module 13 and the simulation runoff computing module 14 of oozing, wherein,

Load module 11 is used to be provided with model parameter, and the input raw data;

Preferably, said load module 11 further comprises:

Model parameter is provided with submodule 111, is used to be provided with underground water and replenishes coefficient, maximumly oozes loss down, the interflow coefficient that effluents, and coefficient of groundwater runoff oozes loss index down, soil water storage capacity and hold back the storage volume parameter as model parameter;

Raw data input submodule 112 is used to import the weather forecast rainfall amount of following certain period and the data that virtual forecast combines with measured discharge, and imports meteorological factor as raw data, and said raw data comprises:

Period rainfall amount, vegetation are held back the savings amount, potential evaporation ability, soil moisture, empirical parameter and underground water pondage.

Surpass and ooze runoff yield module 12, be used to judge that the runoff yield mode is to surpass when oozing runoff yield, calculate rainwash, said rainwash will be as the simulation runoff;

The said ultra runoff yield module 12 of oozing is calculated vegetation according to the following equation and is held back residual flow:

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value;

Saidly ultra ooze the runoff yield module said vegetation is held back residual flow as said rainwash.

Runoff yield under saturated storage module 13 is used to judge when the runoff yield mode is runoff yield under saturated storage, calculates milliosmolarity under the soil, and utilizes milliosmolarity calculating base flow and interflow under the said soil;

Preferably, said runoff yield under saturated storage module 13 further comprises:

Milliosmolarity calculating sub module 131 under the soil is used to calculate milliosmolarity under the soil, infiltration rate and vegetation is held back got minimum numerical value in the residual flow as milliosmolarity under the soil;

Said infiltration rate does

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

Wherein, INF is an infiltration rate, and COEFF oozes loss under maximum, and S oozes loss index under being, SMS is a soil moisture, and SMSC is the soil water storage capacity;

Said vegetation is held back residual flow

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value.

Interflow calculating sub module 132 is used to calculate interflow, and interflow is calculated according to formula:

$\mathrm{SRUN}=\mathrm{SUB}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{RMO}$

Wherein, SRUN is an interflow, and SUB is the interflow coefficient that effluents, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil;

Base flow calculating sub module 133 is used for calculating the soil water storage amount according to milliosmolarity under the soil; Judge whether the soil water storage amount reaches capacity; When the soil water storage amount reaches capacity, calculate the underground water pondage; Judge whether the underground water pondage reaches capacity; When the underground water pondage reaches capacity, calculate base flow.

Preferably, base flow calculating sub module 133 further can comprise:

Soil water storage amount computing unit 1331 is used to calculate the soil water storage amount, and soil moisture adds that the soil moisture magnitude of recruitment is as said soil water storage amount;

Milliosmolarity deducts interflow under the soil, deducts underground water retaining magnitude of recruitment again as said soil moisture magnitude of recruitment.

Said underground water retaining magnitude of recruitment does

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

Wherein, REC is that underground water replenishes pondage, and CRAK is that underground water replenishes coefficient, and U is an empirical parameter, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil, and SRUN is an interflow.

Underground water pondage computing unit 1332 is used to calculate the underground water pondage, and underground water retaining magnitude of recruitment adds that the underground water pondage of raw data input is as said underground water pondage;

Base flow computing unit 1333 is used to calculate base flow, and coefficient of groundwater runoff multiply by the underground water pondage as said base flow.

Simulation runoff computing module 14 is used for calculating the simulation runoff, if the runoff yield mode is to surpass to ooze runoff yield, obtains simulating runoff according to said rainwash; If the runoff yield mode is a runoff yield under saturated storage, when soil is unsaturated, calculate the simulation runoff according to said base flow and interflow, when soil saturation, also calculate rainwash, and calculate the simulation runoff according to said base flow, interflow and rainwash.

Said simulation runoff computing module 14 is used for calculating the simulation runoff, comprising:

If the runoff yield mode is the ultra runoff yield that oozes, with said rainwash as the simulation runoff;

If the runoff yield mode is a runoff yield under saturated storage, when soil was unsaturated, base flow added interflow as the simulation runoff, and when soil saturation, base flow adds interflow, adds rainwash as the simulation runoff.

For system embodiment, because it is similar basically with method embodiment, so description is fairly simple, relevant part gets final product referring to the part explanation of method embodiment.

Each embodiment in this instructions all adopts the mode of going forward one by one to describe, and what each embodiment stressed all is and the difference of other embodiment that identical similar part is mutually referring to getting final product between each embodiment.

More than to a kind of small watershed flood forecasting method and system provided by the present invention based on land gas coupling; Carried out detailed introduction; Used concrete example among this paper principle of the present invention and embodiment are set forth, the explanation of above embodiment just is used for helping to understand method of the present invention and core concept thereof; Simultaneously, for one of ordinary skill in the art, according to thought of the present invention, the part that on embodiment and range of application, all can change, in sum, this description should not be construed as limitation of the present invention.

Claims (18)

1. the small watershed flood forecasting method based on the coupling of land gas is characterized in that, comprising:

Model parameter is set;

The input raw data;

Judge the runoff yield mode through analyzing raw data,, calculate rainwash if the runoff yield mode is the ultra runoff yield that oozes, with said rainwash as the simulation runoff;

If the runoff yield mode is a runoff yield under saturated storage, calculates milliosmolarity under the soil, and utilize milliosmolarity calculating base flow and interflow under the said soil;

When soil is unsaturated, calculate the simulation runoff according to said base flow and interflow;

When soil saturation, also calculate rainwash, and calculate the simulation runoff according to said base flow, interflow and rainwash.

2. method according to claim 1 is characterized in that, model parameter is set, and comprising:

Underground water is set replenishes coefficient, maximumly ooze loss down, the interflow coefficient that effluents, coefficient of groundwater runoff oozes loss index down, soil water storage capacity and hold back the storage volume parameter as model parameter.

3. method according to claim 1 is characterized in that, the input raw data comprises:

The weather forecast rainfall amount of following certain period of input and the data that virtual forecast combines with measured discharge, and import meteorological factor as raw data, said raw data comprises:

Period rainfall amount, vegetation are held back the savings amount, potential evaporation ability, soil moisture, empirical parameter and underground water pondage.

4. method according to claim 1 is characterized in that, when the runoff yield mode is ultra when oozing runoff yield, said calculating rainwash comprises:

Calculate vegetation according to the following equation and hold back residual flow:

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value;

Said vegetation is held back residual flow as said rainwash.

5. method according to claim 1 is characterized in that, calculates milliosmolarity under the soil, comprising:

Infiltration rate and vegetation are held back and get minimum numerical value in the residual flow as milliosmolarity under the soil;

Said infiltration rate does

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

Wherein, INF is an infiltration rate, and COEFF oozes loss under maximum, and S oozes loss index under being, SMS is a soil moisture, and SMSC is the soil water storage capacity;

Said vegetation is held back residual flow

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value.

6. method according to claim 1 is characterized in that, utilizes milliosmolarity calculating interflow under the said soil, comprising:

Calculate interflow according to formula:

$\mathrm{SRUN}=\mathrm{SUB}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{RMO}$

Wherein, SRUN is an interflow, and SUB is the interflow coefficient that effluents, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil.

7. according to the arbitrary described method of claim 1 to 3, it is characterized in that, utilize milliosmolarity calculating base flow under the said soil, comprising:

Calculate the soil water storage amount according to milliosmolarity under the soil;

Judge whether the soil water storage amount reaches capacity;

When the soil water storage amount reaches capacity, calculate the underground water pondage;

Judge whether the underground water pondage reaches capacity;

When the underground water pondage reaches capacity, calculate base flow.

8. method according to claim 7 is characterized in that, calculates the soil water storage amount according to milliosmolarity under the soil, comprising:

Soil moisture adds that the soil moisture magnitude of recruitment is as said soil water storage amount;

Milliosmolarity deducts interflow under the soil, deducts underground water retaining magnitude of recruitment again as said soil moisture magnitude of recruitment.

Said underground water retaining magnitude of recruitment does

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

Wherein, REC is the underground water pondage, and CRAK is that underground water replenishes coefficient, and U is an empirical parameter, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil, and SRUN is an interflow.

9. method according to claim 8 is characterized in that, calculates the underground water pondage, comprising:

Underground water retaining magnitude of recruitment adds that the underground water pondage of raw data input is as said underground water pondage.

10. method according to claim 7 is characterized in that, calculates base flow, comprising:

Coefficient of groundwater runoff multiply by the underground water pondage as said base flow.

11. method according to claim 5 is characterized in that, when soil saturation, calculates rainwash, comprising:

Vegetation is held back residual flow and deducts under the soil milliosmolarity as said rainwash.

12. method according to claim 1 is characterized in that:

When soil is unsaturated, calculates the simulation runoff according to said base flow and interflow and comprise:

Base flow adds that interflow is as said simulation runoff;

When soil saturation, calculate the simulation runoff according to said base flow, interflow and rainwash and comprise:

Base flow adds interflow, adds rainwash as the simulation runoff.

13. the small watershed flood forecast system based on the coupling of land gas is characterized in that, comprising:

Load module is used to be provided with model parameter, and the input raw data;

Surpass and ooze the runoff yield module, be used to judge that the runoff yield mode is to surpass when oozing runoff yield, calculate rainwash, said rainwash will be as the simulation runoff;

The runoff yield under saturated storage module is used to judge when the runoff yield mode is runoff yield under saturated storage, calculates milliosmolarity under the soil, and utilizes milliosmolarity calculating base flow and interflow under the said soil;

Simulation runoff computing module is used for calculating the simulation runoff, if the runoff yield mode is to surpass to ooze runoff yield, obtains simulating runoff according to said rainwash; If the runoff yield mode is a runoff yield under saturated storage, when soil is unsaturated, calculate the simulation runoff according to said base flow and interflow, when soil saturation, also calculate rainwash, and calculate the simulation runoff according to said base flow, interflow and rainwash.

14. system according to claim 13 is characterized in that, said load module comprises:

Model parameter is provided with submodule, is used to be provided with underground water and replenishes coefficient, maximumly oozes loss down, the interflow coefficient that effluents, and coefficient of groundwater runoff oozes loss index down, soil water storage capacity and hold back the storage volume parameter as model parameter;

Raw data input submodule is used to import the weather forecast rainfall amount of following certain period and the data that virtual forecast combines with measured discharge, and imports meteorological factor as raw data, and said raw data comprises:

Period rainfall amount, vegetation are held back the savings amount, potential evaporation ability, soil moisture, empirical parameter and underground water pondage.

15. system according to claim 13 is characterized in that:

The said ultra runoff yield module of oozing is calculated vegetation according to the following equation and is held back residual flow:

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value;

Saidly ultra ooze the runoff yield module said vegetation is held back residual flow as said rainwash.

16. system according to claim 13 is characterized in that, said runoff yield under saturated storage module comprises:

Milliosmolarity calculating sub module under the soil is used to calculate milliosmolarity under the soil, infiltration rate and vegetation is held back got minimum numerical value in the residual flow as milliosmolarity under the said soil;

Said infiltration rate does

$\mathrm{INF}=\mathrm{COEFF}\×e^{0.95*S^{\frac{3}{2}}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}}$

Wherein, INF is an infiltration rate, and COEFF oozes loss under maximum, and S oozes loss index under being, SMS is a soil moisture, and SMSC is the soil water storage capacity;

Said vegetation is held back residual flow

INR＝MAX[(RAIN+INS-INSC)，0]

Wherein, INR is that vegetation is held back residual flow, and RIAN is a period quantity of precipitation, and INS is the vegetation savings amount of damming, and INSC is for holding back the savings capacity parameter, and MAX representes to get big numerical value in two numerical value.

The interflow calculating sub module is used to calculate interflow, and interflow is calculated according to formula:

$\mathrm{SRUN}=\mathrm{SUB}\×\frac{\mathrm{SMS}}{\mathrm{SMSC}}\×\mathrm{RMO}$

Wherein, SRUN is an interflow, and SUB is the interflow coefficient that effluents, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil;

The base flow calculating sub module is used for calculating the soil water storage amount according to milliosmolarity under the soil; Judge whether the soil water storage amount reaches capacity; When the soil water storage amount reaches capacity, calculate the underground water pondage; Judge whether the underground water pondage reaches capacity; When the underground water pondage reaches capacity, calculate base flow.

17. system according to claim 16 is characterized in that, the base flow calculating sub module comprises:

Soil water storage amount computing unit is used to calculate the soil water storage amount, and soil moisture adds that the soil moisture magnitude of recruitment is as said soil water storage amount;

Milliosmolarity deducts interflow under the soil, deducts underground water retaining magnitude of recruitment again as said soil moisture magnitude of recruitment.

Said underground water retaining magnitude of recruitment does

$\mathrm{REC}=\mathrm{CRAK}\×\frac{U\×\mathrm{SMS}}{\mathrm{SMSC}+\mathrm{SMS}}\×(\mathrm{RMO}-\mathrm{SRUN})$

Wherein, REC is the underground water pondage, and CRAK is that underground water replenishes coefficient, and U is an empirical parameter, and SMS is a soil moisture, and SMSC is the soil water storage capacity, and RMO is a milliosmolarity under the soil, and SRUN is an interflow.

Underground water pondage computing unit is used to calculate the underground water pondage, and underground water retaining magnitude of recruitment adds that the underground water pondage of raw data input is as said underground water pondage;

The base flow computing unit is used to calculate base flow, and coefficient of groundwater runoff multiply by the underground water pondage as said base flow.

18. system according to claim 13 is characterized in that,

Said simulation runoff computing module calculates by following method:

If the runoff yield mode is the ultra runoff yield that oozes, with said rainwash as the simulation runoff;

If the runoff yield mode is a runoff yield under saturated storage, when soil was unsaturated, base flow added interflow as the simulation runoff, and when soil saturation, base flow adds interflow, adds rainwash as the simulation runoff.

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