JPH0148489B2 - - Google Patents
Info
- Publication number
- JPH0148489B2 JPH0148489B2 JP57059068A JP5906882A JPH0148489B2 JP H0148489 B2 JPH0148489 B2 JP H0148489B2 JP 57059068 A JP57059068 A JP 57059068A JP 5906882 A JP5906882 A JP 5906882A JP H0148489 B2 JPH0148489 B2 JP H0148489B2
- Authority
- JP
- Japan
- Prior art keywords
- river
- runoff
- flow rate
- moisture content
- soil moisture
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000002689 soil Substances 0.000 claims description 23
- 238000000034 method Methods 0.000 claims description 9
- 238000012876 topography Methods 0.000 claims description 2
- 238000005259 measurement Methods 0.000 description 8
- 238000010586 diagram Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000007423 decrease Effects 0.000 description 3
- 238000013507 mapping Methods 0.000 description 2
- 238000006424 Flood reaction Methods 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
- G01F1/00—Measuring the volume flow or mass flow of fluid or fluent solid material wherein the fluid passes through a meter in a continuous flow
Landscapes
- Physics & Mathematics (AREA)
- Fluid Mechanics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Volume Flow (AREA)
Description
本発明は、降雨強度と土壞水分率とを測定し、
その測定値から河川流出流量の変動を高精度で予
測する方法に関する。
従来、降雨と河川流出の相関について、単位流
量図法が提唱され、一般に利用されている。
単位流量図法は、
(1) 継続時間の等しい降雨による河川の流出流量
（Ｑ）は降雨強度（Ｒ）に比例するが、流出流
量最大値（Qp）の出現の時点、即ち降雨開始
時点よりの時間おくれ（tp）、および流出流量
の増加の期間（Ｔ）は降雨強度の大小にかかわ
りなく一定である。
(2) 継続時間が等しく、かつ出現時刻の異なる降
雨による河川流出流量の変化は、各個々の降雨
による河川流出流量、時間曲線の合成、即ち同
一時間軸における河川流量の加算値によつて示
される合成流出流量曲線で示される。
という基本仮定に基ずいており、対象河川流域に
対し、単位時間だけ、一定強度の降雨があつた場
合の、河川流出流量（Ｑ）の変化曲線を、当該河
川の単位流量図と規定する。
ここで、単位流量図の形状を規定する要素とし
て、
(イ) 流出流量最大値（Qp）
(ロ) 降雨開始後Qp出現までの時間おくれ（tp）
(ハ) 流出流量（Ｑ）の減少特性
があげられるが、これ等は対象河川の流域の特性
によつて規定される変数であり、わが国の河川で
は、近似的に次式が提示されている。
(a) Ｑの上昇曲線
Ｑ／Qp＝（ｔ／tp）2.4 ……(1)
(b) Ｑの減水曲線
１＞Ｑ／Qp≧0.3の場合
0.3＞Ｑ／Qp≧0.32の場合
0.32≧Ｑ／Qpの場合
ここにQp（m3／ｓ）…単位時間tp（ｈ）、降雨強
度Ｒ（mm）による最大流出流量
tk（hr）……Qpが0.3Qpまでに減少する時間
を示す。
(c) Qpの算出
Qp＝0.2778A・Ｒ／0.3tp＋tk ……(5)
ここにＡ（Km2）……流域面積
Ｒ（mm）……降雨強度
しかしながら上述の単位流量図法による河川流
出量の算定は、実際の河川においては、降雨強度
の増加に伴い、tpが減少し、流出流量最大値
（Qp）が降雨強度比以上に増加する傾向があり、
実情と合致しない。すなわち前述の基本仮定は成
立せず予測精度を大きく低下させ実用上問題が多
い。
本発明は、従来の河川流出流量予測におけるこ
の欠点を除去するために、河川流域の性格を代表
する地点の降雨強度及び土壞水分率の連続測定を
実施して、各単位時間の降雨強度及び土壞水分率
を得て、あらかじめ規定されている当該河川個有
の降雨強度、土壤水分率と河川流出流量との相関
関係を記憶させた演算装置に入力させることによ
り、より高精度の河川流出量変化を、より速かに
予測しようとするものである。
本発明は、まず前述の単位流量図法の第一の基
本仮定条件、(1)を次の（1a）のように変更する。
（1a） 継続時間の等しい降雨による河川の流
出流量最大値（Qp）、流出流量最大値の降雨開
始時点よりの時間おくれ（tp）、流出流量の変
化の期間（Ｔ）は、降雨量をＲ、土壌水分率を
ｗとすれば当該河川個有の関数として
Qp＝f1（Ｒ、ｗ） ……(6)
tp＝f2（Ｒ、ｗ） ……(7)
Ｔ＝f3（Ｒ、ｗ） ……(8)
で表わされる相関関係を有する。
本発明者らは実験の結果、基本仮定条件を上述
のように変更すれば前述の単位流量図法の条件、
手段をそのまま採用することによつて、実際の河
川の実情に即した河川流出流量を高精度で予測す
ることが可能となることを見出した。
本発明は上記知見に基いて完成されたもので、
その要旨とするところは、河川流域内の土質、土
壞構造、および地形を類型別に区分し、該区分地
域内の代表的な地点の降雨強度と土壞水分率とを
測定し、この測定値を演算装置に入力し、この演
算装置にあらかじめ記憶させた降雨強度と土壌水
分率と河川流出流量との相関関係を利用して河川
流出流量を予測することを特徴とする河川流出流
量予測方法にある。
次に、本発明の実施例の１例について詳述す
る。実験した河川の流域面積は約2.8Km2のだ円形
状で、その短軸方向に30゜〜15゜の傾斜をしてお
り、中心を通る長軸にそつて小河川が形成されて
いる。
流域の特性の代表地点として、地図、地質図、
および現地調査の結果、だ円面積の長軸上の重心
附近の点を選定し、ここにてんとうます式自記雨
量記録計と、誘電率測定型土壞水分自記記録計
（測定位置は地表より40cmの地中埋設）を設け、
更に河川流出量の測定には、前記流域の出口にせ
き式流量計を設置し、各々１時間毎に測定を実施
し、６ケ月の測定データーでこの河川の特性をも
とめた。
第１図に、前述の６ケ月の測定データーより求
めた本河川流域の降雨強度、土壞水分率に対応す
る流出流量変化量（m3／ｓ）の相関関係図を示
す。
第１図から、土壌水分率が57％附近を境とし
て、その上、下における降雨強度と河川流出流量
との関係が大幅に異なつていることがわかる。
第１図の相関関係を演算装置に記憶させ、降雨
強度と土壌水分率とを実測し、流出流量を予測し
た結果を第１表に示し、実測した流出流量と共に
第２図に図示した。
The present invention measures rainfall intensity and soil moisture content,
This paper relates to a method for predicting fluctuations in river runoff with high accuracy from the measured values. Conventionally, a unit discharge mapping method has been proposed and commonly used for the correlation between rainfall and river runoff. The unit flow projection method is as follows: (1) River runoff (Q) due to rainfall of equal duration is proportional to rainfall intensity (R), but from the time when the maximum runoff flow (Q p ) appears, that is, from the start of rainfall. The time delay (t p ) and the period of increase in runoff flow rate (T) are constant regardless of the rainfall intensity. (2) Changes in river runoff due to rainfall events of equal duration but at different times of appearance are expressed by the composition of the river runoff and time curves for each individual rainfall event, that is, the sum of the river flow rates on the same time axis. This is shown by the composite effluent flow rate curve. Based on this basic assumption, the change curve of the river runoff (Q) when rainfall of a certain intensity falls on the target river basin for a unit time is defined as the unit flow diagram of the river. Here, the elements that define the shape of the unit flow diagram are: (a) Maximum runoff flow rate (Q p ) (b) Time lag from the start of rainfall to the appearance of Q p (t p ) (c) Runoff flow rate (Q) However, these are variables determined by the characteristics of the target river basin, and for rivers in Japan, the following equation is proposed as an approximation. (a) Rising curve of Q Q/Q p = (t/t p ) 2.4 ……(1) (b) Decreasing curve of Q When 1>Q/Q p ≧0.3 If 0.3>Q/Q p ≧0.3 2 0.3 2 ≧Q/Q p Here, Q p (m 3 /s)...maximum runoff flow rate t k (hr) based on unit time t p (h) and rainfall intensity R (mm)... indicates the time for Q p to decrease to 0.3Q p . (c) Calculation of Q p Q p = 0.2778A・R/0.3t p + t k ...(5) Here A (Km 2 ) ... Basin area R (mm) ... Rainfall intensity However, the above-mentioned unit flow projection method Calculating river runoff using
It doesn't match the reality. In other words, the above-mentioned basic assumption does not hold true, greatly reducing prediction accuracy and causing many practical problems. In order to eliminate this drawback in conventional river runoff prediction, the present invention continuously measures rainfall intensity and soil moisture content at points representative of the characteristics of the river basin, and calculates the rainfall intensity and soil moisture content for each unit time. By obtaining the soil moisture content and inputting it into a calculation device that stores predefined rainfall intensity specific to the river concerned, and the correlation between soil moisture content and river runoff flow rate, more accurate river runoff can be calculated. The aim is to predict changes in quantity more quickly. The present invention first changes the first basic assumption (1) of the above-described unit flow rate mapping method to the following (1a). (1a) The maximum value of river runoff due to rainfall of equal duration (Q p ), the time lag between the maximum value of runoff from the start of rain (t p ), and the period of change in runoff (T) are determined by the amount of rainfall. If R is R and the soil moisture rate is w, then as a function specific to the river, Q p = f 1 (R, w) ... (6) t p = f 2 (R, w) ... (7) T = f 3 (R, w) ...(8) It has a correlation expressed as follows. As a result of experiments, the present inventors have found that if the basic assumptions are changed as described above, the conditions of the unit flow diagram described above,
It has been found that by employing the method as is, it is possible to predict river runoff with high accuracy in accordance with the actual conditions of the river. The present invention was completed based on the above findings,
The gist of this is to classify the soil quality, soil structure, and topography within the river basin by type, measure the rainfall intensity and soil moisture content at representative points within the classified area, and calculate the measured values. A method for predicting river runoff flow rate, characterized in that the river runoff flow rate is predicted by inputting the information into a calculation device and using the correlation between rainfall intensity, soil moisture content, and river runoff amount stored in advance in the calculation device. be. Next, one example of the embodiment of the present invention will be described in detail. The basin area of the river tested was an ellipse with an area of approximately 2.8 km 2 and an inclination of 30° to 15° along its short axis, with small rivers forming along the long axis passing through the center. Maps, geological maps,
As a result of the on-site survey, we selected a point near the center of gravity on the long axis of the ellipse area, and installed a ladybug-type self-recording rainfall recorder and a dielectric constant measurement-type soil moisture recorder (measurement position is 40 cm from the ground surface). (buried underground),
Furthermore, to measure the river runoff, a weir-type flowmeter was installed at the outlet of the basin, measurements were taken every hour, and the characteristics of this river were determined from the six months of measurement data. Figure 1 shows a correlation diagram of the amount of change in runoff flow rate (m 3 /s) corresponding to the rainfall intensity and soil moisture content in this river basin, determined from the six months of measurement data mentioned above. From Figure 1, it can be seen that the relationship between rainfall intensity and river runoff differs significantly above and below the soil moisture content of 57%. The correlation shown in Figure 1 was stored in a computing device, rainfall intensity and soil moisture content were actually measured, and the runoff flow rate was predicted.The results are shown in Table 1 and illustrated in Figure 2 together with the actually measured runoff flow rate.
【表】【table】
【表】
第１表は、測定開始以降の流出流量の変化量を
示すもので、既存流出流量は測定開始時を零とし
て表示してある。既存流出流量は、当該河川の特
性から予測されるもので、本実施例の河川では実
測点における降雨強度、土壞水分率と流出流量と
の関係から、次のような特性が得られていた。
(1) 降雨強度が前測定値より増加したときは既存
流出量は前予測流出流量とほぼひとしい。
(2) 降雨強度が前測定値より減少したときは、既
存流出量は前予測流出流量に一定の減水率を乗
じた値に減少する。
減水率は、この例では１時間目0.90、２時間
目0.77、３時間目0.67、…となつている。
第２図は降雨強度、土壌水分率、河川流出流量
の実測値と本発明による河川流出流量予測値とを
描いたものである。第２図から、本発明方法によ
る流出流量予測が極めて高精度であることがわか
る。
本発明は、適切に区分された流域内の多数の地
点の単位時間の降雨強度、並びにその時点の土壞
水分率を測定、集約し、適切な演算処理を実施す
ることによつて、大河川の流出流量を綜合的に高
精度で予測し把握することができ、洪水時のみで
なく、年間を通じて合理的な利水管理を可能とす
るもので、ダム貯水位の合理的制御によつて、上
水道、濃業用水、発電等の管理に寄与するところ
が大である。[Table] Table 1 shows the amount of change in the outflow flow rate since the start of measurement, and the existing outflow flow rate is displayed with the time at the start of measurement as zero. The existing runoff flow rate is predicted from the characteristics of the river in question, and the following characteristics were obtained for the river in this example from the relationship between rainfall intensity, soil moisture content, and runoff flow rate at the actual measurement point. . (1) When the rainfall intensity increases from the previous measured value, the existing runoff volume is almost equal to the previously predicted runoff volume. (2) When the rainfall intensity decreases from the previous measured value, the existing runoff volume decreases to the value obtained by multiplying the previous predicted runoff volume by a certain water reduction rate. In this example, the water reduction rate is 0.90 for the first hour, 0.77 for the second hour, 0.67 for the third hour, and so on. FIG. 2 depicts actually measured values of rainfall intensity, soil moisture content, and river runoff flow rate, and predicted values of river runoff flow rate according to the present invention. From FIG. 2, it can be seen that the outflow flow rate prediction by the method of the present invention is extremely accurate. The present invention measures and aggregates the rainfall intensity per unit time at many points in an appropriately divided watershed, as well as the soil moisture content at that point, and performs appropriate calculation processing. It is possible to comprehensively predict and understand the flow rate of water outflow with high precision, making it possible to rationally manage water usage not only during floods but throughout the year. It greatly contributes to the management of industrial water, power generation, etc.
第１図は降雨強度、土壞水分率と河川流出流量
変化との相関関係を例示するグラフ。第２図は、
降雨強度、土壞水分率と河川流出流量実測値と、
河川流出流量予測値との例を示すグラフである。
Figure 1 is a graph illustrating the correlation between rainfall intensity, soil moisture content, and changes in river runoff. Figure 2 shows
Actual measurements of rainfall intensity, soil moisture content, and river runoff flow,
It is a graph which shows an example with a river runoff flow volume prediction value.
Claims (1)
類型別に区別し、該区分地域内の代表的な地点の
降雨強度と土壞水分率とを測定し、該測定値を演
算装置に入力し、該演算装置にあらかじめ記憶さ
せた降雨強度と土壞水分率と河川流出流量との相
関関係を利用して河川流出流量を予測することを
特徴とする河川流出流量予測方法。1. Classify the soil quality, soil structure, and topography within the river basin by type, measure the rainfall intensity and soil moisture content at representative points within the classified area, and input the measured values into a calculation device. A river runoff flow rate prediction method, comprising predicting a river runoff flow rate using a correlation between rainfall intensity, soil moisture content, and river runoff flow rate that is stored in advance in the arithmetic device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57059068A JPS58176518A (en) | 1982-04-09 | 1982-04-09 | Forecasting method of river effluent |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP57059068A JPS58176518A (en) | 1982-04-09 | 1982-04-09 | Forecasting method of river effluent |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS58176518A JPS58176518A (en) | 1983-10-17 |
| JPH0148489B2 true JPH0148489B2 (en) | 1989-10-19 |
Family
ID=13102661
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP57059068A Granted JPS58176518A (en) | 1982-04-09 | 1982-04-09 | Forecasting method of river effluent |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS58176518A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11401106B2 (en) | 2009-06-17 | 2022-08-02 | Koninklijke Douwe Egberts B.V. | Capsule, system and method for preparing a predetermined quantity of beverage suitable for consumption |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2014052328A (en) * | 2012-09-10 | 2014-03-20 | Toshiba Corp | Natural dam observation system, observation device, and observation method |
-
1982
- 1982-04-09 JP JP57059068A patent/JPS58176518A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11401106B2 (en) | 2009-06-17 | 2022-08-02 | Koninklijke Douwe Egberts B.V. | Capsule, system and method for preparing a predetermined quantity of beverage suitable for consumption |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS58176518A (en) | 1983-10-17 |
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