Comprehensive reconstruction method for long-series sediment data in data-lacking areas

Abstract

A comprehensive reconstruction method for long-series sediment data in data-lacking areas includes steps of: collecting hydrological and sediment data of a target river section; calculating sediment data in data-rich years with a flow-sediment content annual relationship curve method; calculating sediment data in only water quality and sediment test years with a correlation method between water quality and sediment data and hydrological station sediment data; calculating sediment data in data-lacking years with an adjacent station same year flow-sediment content relationship curve method; and calculating sediment data in remaining years with a multi-year average flow-sediment content relationship curve method. The method comprehensively adopts four methods to reconstruct the long-series sediment data based on sediment actual observation and characteristics in the data-lacking areas, which can make up for the limitations and deficiencies between the four methods, and the required data is easier to collect than those in the conventional methods.

Claims

1. A comprehensive reconstruction method for long-series sediment data in data-lacking areas, comprising steps of: 1) collecting hydrological and sediment data of a target river section, wherein the hydrological and sediment data comprises: a hydrological station long-series daily flow Q.sub.i,j,k, a sediment content TS.sub.i,n,k and a flow q.sub.i,n,k during sediment test, and a surface sediment test sediment content C.sub.i,m,k and a flow cq.sub.i,m,k during water quality test, wherein i=1˜Nyear, Nyear is long-series years; j=1˜Nday(i), Nday(i) is a total number of days in a year i; k=1˜Nsta, Nsta is a quantity of hydrological stations; n=1˜Nsam(i,k), Nsam(i,k) is a quantity of sediment test samples at a hydrological station k in the year i; m=1˜NCsam(i,k), NCsam(i,k) is a quantity of surface sediment test samples of the hydrological station k in the year i; 2) calculating sediment data in data-rich years with a flow-sediment content annual relationship curve method; wherein the flow-sediment content annual relationship curve method comprises specific steps of: identifying the data-rich years according to following principles: (1) there are the sediment test samples in each month of a flood season; and (2) annual samples are not less than a certain number Nsmin; establishing an annual flow-sediment content relationship curve with sediment test data TS.sub.i,n,k and q.sub.i,n,k of the data-rich years:
TS.sub.i,k=f.sub.1(q.sub.i,k)  (1) using a significance level a=0.05 and p<0.01 to test whether the annual flow-sediment content relationship curve established passes a t test; if not, removing the year from the data-rich years; otherwise, calculating daily sediment content data of the year with the equation (1):
S.sub.i,k=f.sub.1(Q.sub.i,k)  (2) then counting an annual sediment transport characteristic value:
TQS.sub.i,k=Σ.sub.j=1.sup.Nday(i)f.sub.1(Q.sub.i,j,k)×Q.sub.i,j,k×dt  (3); 3) calculating sediment data in only water quality and sediment test years with a correlation method between water quality and sediment data and hydrological station sediment data; wherein the correlation method comprises specific steps of: selecting years having the surface sediment test samples of the water quality test from the data-rich years, and establishing a surface sediment content-flow relationship curve with the surface sediment test sediment content C.sub.i,m,k and the flow cq.sub.i,m,k of the years:
C.sub.i,k=f.sub.2(cq.sub.i,k)  (4) according to the equation (4), calculating an annual surface sediment transport characteristic value:
TQC.sub.i,k=Σ.sub.j=1.sup.Nday(i)f.sub.2(Q.sub.i,j,k)×Q.sub.i,j,k×dt  (5) according to the equations (3) and (5), establishing a relationship curve of an annual sediment transport and an annual surface sediment transport of the hydrological station k in years with rich sediment test data and water quality surface sediment test data:
TQS.sub.k=f.sub.3(TQC.sub.k)  (6) according to the equations (6) and (4), calculating daily sediment data in years with the water quality surface sediment test data but without the rich sediment test data:
S.sub.i,j,k=f.sub.3(f.sub.2(Q.sub.i,j,k)×Q.sub.i,j,k)/Q.sub.i,j,k  (7); 4) calculating sediment data in data-lacking years with an adjacent station same year flow-sediment content relationship curve method; 5) calculating sediment data in remaining years with a multi-year average flow-sediment content relationship curve method; and 6) applying the sediment data to sediment research and design in river protection, management and development in data-lacking areas.

2. The comprehensive reconstruction method, as recited in claim 1, wherein the step 4) specifically comprises steps of: selecting years which are data-rich years of both of adjacent hydrological stations k and k+1, and establishing an annual sediment transport relationship curve of the adjacent stations according to the equation (3):
TQS.sub.k=f.sub.4(TQS.sub.k+1)  (8) using the significance level a=0.05 and p<0.01 to test whether the relationship curve (8) established passes the t test; if not, there is no obvious correlation between the adjacent stations, and the method cannot be applied; otherwise, calculating the sediment data of the same year of the hydrological station k and the data-lacking years with the equation (8) and the equation (2) of a water-sediment relationship curve in the data-rich years of the hydrological station k+1:
S.sub.i,j,k=f.sub.4(f.sub.1,k+1(Q.sub.i,j,k)×Q.sub.i,j,k)/Q.sub.i,j,k  (9).

3. The comprehensive reconstruction method, as recited in claim 2, wherein the step 5) specifically comprises steps of: establishing a multi-year average flow-sediment content relationship curve with the sediment test data TS.sub.i,n,k and q.sub.i,n,k of the data-rich years:
TS.sub.k=f.sub.5(q.sub.k)  (10) for years where none of the three methods of the steps 2)-4) is applicable, calculating the daily sediment content data with the equation (10):
S.sub.k=f.sub.5(Q.sub.k)  (11).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a flow chart of a comprehensive reconstruction method for long-series sediment data in data-lacking areas according to an embodiment of the present invention;

(2) FIG. 2 illustrates a relationship between water quality and sediment data and hydrological station sediment data according to the embodiment of the present invention;

(3) FIG. 3 illustrates a comprehensive reconstruction result of the long-series sediment data according to the embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

(4) The technical solutions in the embodiment of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiment is only one of all embodiments of the present invention. Based on the embodiment of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

(5) Referring to FIGS. 1-3, the present invention provides a comprehensive reconstruction method for long-series sediment data in data-lacking areas, whose basic ideas are: first, calculating sediment data in data-rich years with a flow-sediment content annual relationship curve method; second, calculating sediment data in only water quality and sediment test years with a correlation method between water quality and sediment data and hydrological station sediment data; third, for years without rich sediment data or water quality and sediment test, calculating with an adjacent station same year flow-sediment content relationship curve method; and finally, for years where the above three methods are not applicable, calculating with a multi-year average flow-sediment content relationship curve method. Detailed processes of the present invention are shown in FIG. 1.

(6) The technical solutions of the present invention will be further described in detail below with the embodiment and the drawings.

(7) A comprehensive reconstruction method for long-series sediment data in data-lacking areas comprises steps of: Step 1, collecting hydrological and sediment data of a target river section, wherein the hydrological and sediment data comprises: a hydrological station long-series daily flow Q.sub.i,j,k, a sediment content TS.sub.i,n,k and a flow q.sub.i,n,k during sediment test, and a surface sediment test sediment content C.sub.i,m,k and a flow cq.sub.i,m,k during water quality test, wherein i=1˜Nyear, Nyear is long-series years; j=1˜Nday(i), Nday(i) is a total number of days in a year i; k=1˜Nsta, Nsta is a quantity of hydrological stations; n=1˜Nsam(i,k), Nsam(i,k) is a quantity of sediment test samples at a hydrological station k in the year i; m=1˜NCsam(i,k), NCsam(i,k) is a quantity of surface sediment test samples of the hydrological station k in the year i; Step 2, calculating sediment data in data-rich years with a flow-sediment content annual relationship curve method; wherein the Step 2 specifically comprises steps of: Step 2.1, identifying the data-rich years; wherein the data-rich years are identified according to following principles: (1) there are the sediment test samples in each month of a flood season; and (2) annual samples are not less than a certain number Nsmin; Step 2.2, establishing an annual flow-sediment content relationship curve; wherein the annual flow-sediment content relationship curve is established with sediment test data TS.sub.i,n,k and q.sub.i,n,k of the data-rich years:
TS.sub.i,k=f.sub.1(q.sub.i,k)  (1) Step 2.3, performing significance level test and calculating the sediment data in the data-rich years: using a significance level a=0.05 and p<0.01 to test whether the annual flow-sediment content relationship curve established passes a t test; if not, removing the year from the data-rich years; otherwise, calculating daily sediment content data of the year with the equation (1):
S.sub.i,k=f.sub.1(Q.sub.i,k)  (2) then counting an annual sediment transport characteristic value:
TQS.sub.i,k=Σ.sub.i=1.sup.Nday(i)f.sub.1(Q.sub.i,j,k)×Q.sub.i,j,k×dt  (3); Step 3, for years without the rich sediment data but with water quality and sediment observation data, calculating sediment data in only water quality and sediment test years with a correlation method between water quality and sediment data and hydrological station sediment data; wherein the Step 3 specifically comprises steps of: Step 3.1, establishing a surface sediment content-flow relationship curve: selecting years having the surface sediment test samples of the water quality test from the data-rich years, and establishing the surface sediment content-flow relationship curve with the surface sediment test sediment content C.sub.i,m,k and the flow cq.sub.i,m,k of the years:
C.sub.i,k=f.sub.2(cq.sub.i,k)  (4) Step 3.2, according to the equation (4), calculating an annual surface sediment transport characteristic value:
TQC.sub.i,k=Σ.sub.i=1.sup.Nday(i)f.sub.2(Q.sub.i,j,k)×Q.sub.i,j,k×dt  (5) Step 3.3, establishing a relationship curve of an annual sediment transport and an annual surface sediment transport: according to the equations (3) and (5), establishing the relationship curve of the annual sediment transport and the annual surface sediment transport of the hydrological station k in years with rich sediment test data and water quality surface sediment test data:
TQS.sub.k=f.sub.3(TQC.sub.k)  (6) Step 3.4, calculating daily sediment data: according to the equations (6) and (4), calculating the daily sediment data in years with the water quality surface sediment test data but without the rich sediment test data:
S.sub.i,j,k=f.sub.3(f.sub.2,(Q.sub.i,j,k)×Q.sub.i,j,k)/Q.sub.i,j,k  (7). Step 4, calculating sediment data in data-lacking years with an adjacent station same year flow-sediment content relationship curve method; wherein the step 4) specifically comprises steps of: Step 4.1, establishing an annual sediment transport relationship curve selecting years which are data-rich years of both of adjacent hydrological stations k and k+1, and calculating the annual sediment transport TQS.sub.i,k and TQS.sub.i,k+1 of the adjacent hydrological stations according to the equation (3), thereby establishing the annual sediment transport relationship curve of the adjacent stations:
TQS.sub.k=f.sub.4(TQS.sub.k+1)  (8) Step 4.2, performing the significance level test: using the significance level a=0.05 and p<0.01 to test whether the relationship curve (8) established passes the t test; if not, there is no obvious correlation between the adjacent stations, and the method cannot be applied; Step 4.3, for the stations passing the test in the Step 4.2, calculating the sediment data of the same year of the hydrological station k and the data-lacking years with the equation (8) and the equation (2) of a water-sediment relationship curve in the data-rich years of the hydrological station k+1:
S.sub.i,j,k=f.sub.4(f.sub.1,k+1(Q.sub.i,j,k)×Q.sub.i,j,k)/Q.sub.i,j,k  (9);
and Step 5, calculating sediment data in remaining years with a multi-year average flow-sediment content relationship curve method; wherein the step 5) specifically comprises steps of: Step 5.1, establishing a multi-year average flow-sediment content relationship curve with the sediment test data TS.sub.i,n,k and q.sub.i,n,k of the data-rich years:
TS.sub.k=f.sub.5(q.sub.k)  (10) Step 5.2, for years where none of the three methods of the steps 2)-4) is applicable, calculating the daily sediment content data with the equation (10):
S.sub.k=f.sub.5(Q.sub.k)  (11).

(8) In addition, although this specification is drafted in accordance with the embodiment, the embodiment may include more than one independent technical solution. The description in the specification is only for clarity, and those skilled in the art should consider the specification as a whole. The technical solutions in the embodiment can also be appropriately combined to form other embodiments which can be understood by those skilled in the art.