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− | [[File:Double ring.JPG|thumb|Double ring]]
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| [[File:Double ring.jpg|thumb|Schematic diagram of double ring infiltrometer illustrating the infiltration of water both vertically, and laterally particularly from the outer ring.]] | | [[File:Double ring.jpg|thumb|Schematic diagram of double ring infiltrometer illustrating the infiltration of water both vertically, and laterally particularly from the outer ring.]] |
| [[File:Bill's double ring.jpg|thumb|Double ring infiltrometer in use]] | | [[File:Bill's double ring.jpg|thumb|Double ring infiltrometer in use]] |
| + | [[File:Double ring.JPG|thumb|Double ring]] |
| + | {{TOClimit|2}} |
| + | ==Principle== |
| + | Using a double ring infiltrometer is a relatively simple (although slow) method of measuring soil the [[hydraulic conductivity]] or ''[[design infiltration rate]]'' of a [[soil]]. |
| + | |
| + | ==Measurements== |
| ===Packing list=== | | ===Packing list=== |
− | • Small ring (28 – 32 cm)
| + | * Small ring (28 – 32 cm) |
− | • Large ring (53 – 57 cm)
| + | * Large ring (53 – 57 cm) |
− | • Sledge hammer for driving rings into ground
| + | * Sledge hammer for driving rings into ground |
− | • Wooden block to distribute force when driving rings into ground
| + | * Wooden block to distribute force when driving rings into ground |
− | • Level
| + | * Level |
− | • Two metal rulers with clips to secure
| + | * Two metal rulers with clips or tape to secure |
− | • Container for water
| + | * Container for water (will water need transporting to site? take more than you think you'll need) |
− | • Screwdriver or similar implement to dislodge rocks
| + | * Screwdriver or similar implement to dislodge rocks |
| + | ** Tarpaulin for working/sitting on? |
| + | ** Sunscreen and/or umbrella! |
| ===Installation=== | | ===Installation=== |
| # Choose or create clear, level ground at the desired test location. | | # Choose or create clear, level ground at the desired test location. |
− | 2. Work with minimal disturbance to the soil within the test area.
| + | # Work with minimal disturbance to the soil within the test area. |
− | 3. Place the wooden block across the ring and use the sledge hammer to drive the ring into the ground by ≥ 5 cm.
| + | # Place the wooden block across the ring and use the sledge hammer to drive the ring into the ground by ≥ 5 cm. |
− | 4. Check that the ring is level in all directions and correct as necessary.
| + | # Check that the ring is level in all directions and correct as necessary. |
− | 5. Repeat with the second ring (note that the order may vary if the rings are of differing heights.
| + | # Repeat with the second ring (note that the order may vary if the rings are of differing heights. |
− | 6. Both rings should be firm into the ground.
| + | # Both rings should be firm into the ground. |
− | 7. Secure the metal rulers to the inside of the rings.
| + | # Secure the metal rulers to the inside of the rings. |
− | Measurements | + | ===Measurements=== |
− | 1. To begin measurements gently pour 5 – 10 cm of water into both the inner and outer rings.
| + | # To begin measurements gently pour 5 – 10 cm of water into both the inner and outer rings. |
− | 2. Measurement of the water depth should be made every 15 minutes for the first hour, 30 minutes in the second hour and then hourly up to 6 hours.
| + | # Measurement of the water depth should be made every 15 minutes for the first hour, 30 minutes in the second hour and then hourly up to 6 hours. |
− | 3. The rings should be covered to reduce evaporation, particularly in hot weather and when the soil is clayey and infiltration is slow.
| + | # The rings should be covered to reduce evaporation, particularly in hot weather and when the soil is clayey and infiltration is slow. |
− | | |
| | | |
| + | ==Calculations== |
| + | Download a copy of our DRI (double ring infiltrometer) spreadsheet for this process. Directions are provided below. |
| | | |
| + | {{#l:DRI.xlsx|Double ring to K}} |
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− |
| |
− | ==Calculations==
| |
− | [[File:DRI.xlsx]]
| |
− | Using the DRI (double ring infiltrometer) spreadsheet
| |
| ===The Solver add-in=== | | ===The Solver add-in=== |
| To use the calculation spreadsheet, an additional add-in must be enabled in your Excel program. | | To use the calculation spreadsheet, an additional add-in must be enabled in your Excel program. |
− | #Go to ‘File’ in you menu toolbar and select ‘Options’ from the menu, | + | # Go to ‘File’ in your menu toolbar and select ‘Options’ from the menu, |
− | #Choose ‘Add-ins’ and then at the bottom of the window, for ‘Manage Add-ins’, select ‘Go’. | + | # Choose ‘Add-ins’ and then at the bottom of the window, for ‘Manage Add-ins’, select ‘Go’. |
− | #Check the box for the ‘Solver’ add-in and then ‘OK’. | + | # Check the box for the ‘Solver’ add-in and then ‘OK’. |
− | #Your new Solver add-in appears on the right end of the ‘Data’ toolbar in the main Excel window. It is useful for solving all kinds of iterative equations. | + | # Your new Solver add-in appears on the right end of the ‘Data’ toolbar in the main Excel window. It is useful for solving all kinds of iterative equations. |
| + | |
| ===Performing calculations=== | | ===Performing calculations=== |
| #Save a new copy of your spreadsheet. | | #Save a new copy of your spreadsheet. |
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| ##‘Solve’! | | ##‘Solve’! |
| ##The solver produces the optimized S and A values to match the model to the field data. | | ##The solver produces the optimized S and A values to match the model to the field data. |
− | ##The saturated hydraulic conductivity (K) is approximated by dividing A by 2/3, where A is the slope of the linear part of the graph. i.e when infiltration rate has stabilized. | + | ##The saturated hydraulic conductivity (K) is approximated by dividing A by 2/3, where A is the slope of the linear part of the graph. i.e when infiltration rate has stabilized. |
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| | | |
− | ==To review== | + | ==External references== |
− | https://www.astm.org/Standards/D3385.htm | + | * https://www.astm.org/Standards/D3385.htm an alternative method which uses Mariotte tubes to maintain a constant water level during testing. |