Inclined Lysimeter

Abstract

To provide an inclined lysimeter capable of quantitatively measuring the amount of infiltrated water from snowmelt water and rainwater that infiltrates into the ground on a slope, and the amount of snow-covered bottom flow that flows down the slope without infiltrating. [Solution] The inclined lysimeter 1 of the present invention is a device for measuring the amount of seepage water, of snowmelt water and rainwater, that infiltrates into the ground and the amount of snowbed flow that flows down the slope without infiltrating within a measurement area within a slope 200. It is a box-shaped device with a bottom and an upper opening 11, and includes a main body 10 that is buried in the slope, a mesh-like partition plate 20 that divides the main body into an upper space 10U and a lower space 10L, sediment 100 that is filled in the upper space, a snowbed flow measuring unit 30 that collects and measures the amount of snowbed flow that flows down the surface of the sediment, and a seepage water measuring unit 40 that collects and measures the amount of seepage water that infiltrates the sediment and reaches the lower space. The snowbed flow measuring unit can measure the amount of snowbed flow, and the seepage water measuring unit can quantitatively measure the amount of seepage water.

Description

[Technical Field]

[0001] The present invention relates to an inclined lysimeter for use on a slope. [Background technology]

[0002] Lysimeters that measure the amount of moisture in soil and the like are known, and among them, those used on sloping land such as slopes are called inclined lysimeters (or slope lysimeters) (see Non-Patent Document 1). For example, Patent Document 1 discloses a variable slope lysimeter device in which a lysimeter body equipped with a soil chamber can be tilted by a dump device. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Chikaarashi et al., Forestry Research Institute Research Report, Study on Water Balance in Slope Lysimeters According to Slope and Soil Layer Conditions, Bull. Forestry & Forest Products Research Institute No.348, 1987 [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 51-085789 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional technology has the problem that it is not possible to quantitatively measure the amount of meltwater and rainwater that permeates into the ground when snow or rain falls on a slope, or the amount of snowbed flow that flows down the slope without permeating.

[0006] In consideration of the above-mentioned problems, the present invention aims to provide an inclined lysimeter that can quantitatively measure the amount of infiltrated water from snowmelt water and rainwater that infiltrates into the ground on a slope, as well as the amount of snowbed flow that flows down the slope without infiltrating. [Means for solving the problem]

[0007] The inclined lysimeter of the present invention is an inclined lysimeter for measuring the amount of seepage water, out of snowmelt water and rainwater, that seeps into the ground in a measurement area within a slope, and the amount of snowbed flow that flows down the slope without seeping in. It is a box-shaped lysimeter with a bottom and an opening at the top, and is characterized by comprising at least: a main body that is buried in the slope; a mesh-like partition plate that divides the main body into an upper space and a lower space; soil that is filled in the upper space; a snowbed flow measuring unit that collects the snowbed flow that has flowed down the surface of the soil and measures its amount; and a seepage water measuring unit that collects the seepage water that has infiltrated the soil and reached the lower space and measures its amount. The present invention is also characterized by further comprising an inflow water measuring unit that measures the amount of inflow water that flows down the slope and reaches the measurement area. [Effects of the Invention]

[0008] According to the present invention, the amount of snow bed flow can be measured by the snow bed flow measuring unit, and the amount of infiltrating water can be quantitatively measured by the infiltrating water measuring unit. Furthermore, by using an inflow water measuring unit, the amount of inflow water flowing down the slope and reaching the measurement area can be quantitatively measured. Measuring the amount of water mentioned above can help clarify the mechanism of slope collapse that occurs during the snow season. [Brief explanation of the drawings]

[0009] [Figure 1] (a) Perspective view of an inclined lysimeter and (b) Perspective view with the lid removed [Figure 2] Plan view of the inclined lysimeter with the lid removed [Figure 3]Vertical cross-sectional views (a) to (c) showing the schematic structure of the main body, partition plate, snow bottom flow measurement section, and infiltration water measurement section. [Figure 4] A longitudinal cross-sectional view showing the structure of the inflow water measurement unit [Figure 5] A longitudinal cross-sectional view showing the flow of inflow water, meltwater, rainwater, seepage water, and snow cover flow. DETAILED DESCRIPTION OF THE INVENTION

[0010] An embodiment of the inclined lysimeter of the present invention will be described. An inclined lysimeter is a device used to measure the amount of snowmelt water and rainwater that infiltrates into the ground and the amount of snowbed flow that flows down the slope without infiltrating into the ground in a measurement area set up on the slope.

[0011] 1 and 2, the inclined lysimeter 1 comprises a main body 10, a partition plate 20, a snow cover bottom flow measurement section 30, a seepage water measurement section 40, and an inflow water measurement section 50. Note that the illustrations omit the pillars, walls, etc. for supporting the main body 10, etc. The main body 10 is a box-shaped body with a bottom and an upper opening 11, and is buried in the measurement area within the slope 200 as shown in Figures 3 and 4. The main body 10 is preferably made of metal such as stainless steel or aluminum, but may also be made of plastic. Side panels 13 extend upward from the upper, left, and right sides of the bottom surface 12 of the main body 10. No side panels 13 are present on the lower side of the main body 10.

[0012] The partition plate 20 is a mesh-like plate that divides the inside of the main body 10 into an upper space 10U and a lower space 10L. Side plates (not shown) are provided below the left and right sides of the partition plate 20. By bringing the lower ends of the side plates into contact with the bottom surface 12, the partition plate 20 can be held in a floating state within the main body 10. As shown in Fig. 3(c), the upper space 10U is filled with soil 100. In order to prevent the soil 100 from flowing out into the lower space 10L through the through-holes of the mesh-like partition plate 20, the surface of the partition plate 20 is first covered with a sheet 101 such as a nonwoven fabric as shown in Fig. 3(b), and then the soil 100 is filled on top of that.

[0013] The snow-covered bed flow measuring unit 30 is a unit for collecting and measuring the amount of snow-covered bed flow that has flowed down the surface of the soil 100. Specifically, the snow-covered bed flow measuring unit 30 includes an upper catchment unit 31, a settling tank 32a, and a flow meter 32b. The upper water collecting section 31 has a box shape that is roughly triangular in plan view and extends downward from the lower end of the upper space 10U, and is provided with side panels 33 that extend upward from the two left and right sides. As shown in Figure 1(a), the top surface of the upper water collecting section 31 is closed with a lid 34. 3 and 5, the snow-covered bottom flow that has flowed down the surface of the sediment 100 enters from the upper side of the upper catchment section 31 and flows downward. An opening 35 is provided at the lowest end of the upper catchment section 31, and one end of a pipe P1 is connected to the opening 35, and the other end is connected to the settling tank 32a. The snow-covered bottom flow passes through the pipe P1 from the opening 35 to the settling tank 32a, where soil particles and the like are settled, and then passes through the pipe P2, where the flow rate is measured by the flow meter 32b, and the flow is discharged to the outside.

[0014] The seepage water measuring unit 40 is a part for collecting and measuring the amount of seepage water that has seeped into the soil 100 filled in the upper space 10U and reached the lower space 10L. Specifically, the seepage water measuring unit 40 includes a lower water collection unit 41, a settling tank 42a, and a flow meter 42b. The lower water collecting section 41 has a generally triangular shape in plan view, extending downward from the lower end of the lower space 10L, and has side panels 43 extending upward from the two left and right sides. As shown in Figure 1(a), the upper surface of the lower water collecting section 41 is closed by a lid 44. 3 and 5, the seepage water that has permeated the soil 100 in the upper space 10U and reached the lower space 10L enters from the upper side of the lower catchment section 41 and flows downward. An opening 45 is provided at the bottom end of the lower catchment section 41, and one end of a pipe P3 is connected to the opening 45 and the other end is connected to the settling tank 42a. The seepage water passes through the pipe P3 from the opening 45 to the settling tank 42a, where soil particles and the like are allowed to settle, and then passes through the pipe P4 where the flow rate is measured by the flow meter 42b and the water is discharged to the outside.

[0015] 1, 4, and 5, inflow water measuring unit 50 is a section for measuring the amount of inflow water that flows down slope 200 and reaches the measurement area. Specifically, inflow water measuring unit 50 includes a water collection unit 51, a settling tank 52a, and a flow meter 52b. The water collecting section 51 has a generally triangular shape in plan view, extending downward from the upper slope 200, and has side panels 53 extending upward from the two left and right sides. As shown in Figure 1(a), the top surface of the water collecting section 51 is closed with a lid 54. Inflow water (snowmelt water, rainwater, etc.) that flows down slope 200 and reaches the measurement area enters from the upper side of water collection section 51 and flows downward. An opening 55 is provided at the lowest end of water collection section 51, and one end of pipe P5 is connected to opening 55 and the other end is connected to settling tank 52a. The inflow water passes from opening 55 through pipe P5 to settling tank 52a, where soil particles and the like are settled, and then passes through pipe P6, where the flow rate is measured by flow meter 52b and the water is discharged to the outside.

[0016] Slope collapses that occur during the snow season are caused by sudden meltwater generated by rising temperatures and rainfall, which infiltrates the slope and raises the groundwater level within the slope. As a result, pore water pressure rises, destabilizing the slope, and sudden precipitation then triggers the collapse. To clarify the mechanism behind this collapse, it is necessary to quantitatively understand the infiltration of snowmelt water into the ground and the flow of snow beneath the snowpack, and to consider the relationship between these and groundwater. As shown in Figures 4 and 5, if the amount of inflow water flowing into the measurement area is A, the amount of snowmelt water and rainwater generated in the measurement area is B (amount of snowmelt water: Bm, amount of rainwater: Br), the amount of infiltration water is C, and the amount of under-snow flow is D, then the water balance in the measurement area is A + B (= Bm + Br) = C + D. Using the inclined lysimeter 1 of the present invention, A, C, and D can be measured. The amount of precipitation B (= Bm + Br) can be observed by installing a rain and snow gauge near the inclined lysimeter 1. [Industrial Applicability]

[0017] The present invention is an inclined lysimeter that can quantitatively measure the amount of infiltrated water from snowmelt water and rainwater that infiltrates into the ground on a slope, as well as the amount of snowbed flow that flows down the slope without infiltrating, and has industrial applicability. [Explanation of symbols]

[0018] P1~P6 Pipes 1. Inclined lysimeter 10 Main body 10U headspace 10L lower space 11 Top opening 12 Bottom 13 Side plate 20 Divider 30 Snow bottom flow measurement section 31 Upper water collection section 32a Sedimentation tank 32b flow meter 33 Side plate 34 Lid 35 Aperture 40 Permeation water measurement section 41 Lower catchment 42a Sedimentation tank 42b flow meter 43 Side plate 44 Lid 45 Aperture 50 Inflow water measurement section 51 Water catchment area 52a Sedimentation tank 52b flow meter 53 Side plate 54 Lid 55 Aperture 100 soil 101 seats 200 Slope

Claims

1. An inclined lysimeter for measuring the amount of infiltrated water from snowmelt water and rainwater that infiltrates into the ground and the amount of snow-covered bottom flow that flows down the slope without infiltrating, within a measurement area within the slope; A main body portion having a box shape with a bottom and an upper opening, which is embedded in the slope; a mesh-like partition plate that divides the inside of the main body into an upper space and a lower space; Soil and sand filled in the upper space; a snow bed flow measuring unit that collects the snow bed flow that has flowed down the surface of the soil and measures its amount; and a seepage water measuring unit that collects the seepage water that has seeped into the soil and reached the lower space and measures the amount of the collected water.

2. 2. The inclined lysimeter according to claim 1, further comprising an inflow water measuring unit that measures the amount of inflow water that flows down the slope and reaches the measurement area.

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