Advection and Groundwater Flow - Revision history

Jhurley: Replaced content with "#REDIRECTGroundwater Flow and Solute Transport"

2020-12-21T22:18:57Z

Replaced content with "#REDIRECTGroundwater Flow and Solute Transport"

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Jhurley: Redirected page to Groundwater Flow and Solute Transport

2020-12-21T22:13:48Z

Redirected page to Groundwater Flow and Solute Transport

Jhurley: /* Mobile Porosity */

2020-12-17T20:12:43Z

‎Mobile Porosity

Jhurley at 19:48, 17 December 2020

2020-12-17T19:48:01Z

Admin at 00:20, 24 November 2020

2020-11-24T00:20:07Z

Admin at 18:38, 24 September 2020

2020-09-24T18:38:16Z

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Jhurley: /* Darcy Velocity and Seepage Velocity */

2020-09-04T19:45:04Z

‎Darcy Velocity and Seepage Velocity

Jhurley: /* Darcy's Law */

2020-09-04T19:42:20Z

‎Darcy's Law

Jhurley at 19:36, 4 September 2020

2020-09-04T19:36:33Z

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Jhurley at 14:33, 3 September 2020

2020-09-03T14:33:54Z

← Older revision		Revision as of 22:13, 21 December 2020
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		+	#REDIRECT[[Groundwater Flow and Solute Transport]]
		+
	Groundwater migrates from areas of higher [[wikipedia: Hydraulic head \| hydraulic head]] toward lower hydraulic head, transporting dissolved solutes through the combined processes of [[wikipedia: Advection \| advection]] and [[wikipedia: Dispersion \| dispersion]]. Advection refers to the bulk movement of solutes carried by flowing groundwater. Dispersion refers to the spreading of the contaminant plume from highly concentrated areas to less concentrated areas. In many groundwater transport models, solute transport is described by the advection-dispersion-reaction equation in which dispersion coefficients can be calculated as the sum of molecular diffusion, mechanical dispersion, and macrodispersion.		Groundwater migrates from areas of higher [[wikipedia: Hydraulic head \| hydraulic head]] toward lower hydraulic head, transporting dissolved solutes through the combined processes of [[wikipedia: Advection \| advection]] and [[wikipedia: Dispersion \| dispersion]]. Advection refers to the bulk movement of solutes carried by flowing groundwater. Dispersion refers to the spreading of the contaminant plume from highly concentrated areas to less concentrated areas. In many groundwater transport models, solute transport is described by the advection-dispersion-reaction equation in which dispersion coefficients can be calculated as the sum of molecular diffusion, mechanical dispersion, and macrodispersion.

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 |Poorly sorted sand and gravel||0.085
 |-
-|Poorly sorted sand and gravel||0.04 — 0.07
+|Poorly sorted sand and gravel||0.04-0.07
 |-
 |Poorly sorted sand and gravel||0.09
 |-
-|Fractured sandstone||0.001 — 0.007
+|Fractured sandstone||0.001-0.007
 |-
 |Alluvial formation||0.102
@@ Line 114: / Line 114: @@
 |Glacial outwash||0.145
 |-
-|Weathered mudstone regolith||0.07 — 0.10
+|Weathered mudstone regolith||0.07-0.10
 |-
 |Alluvial formation||0.07
@@ Line 122: / Line 122: @@
 |Silty sand||0.05
 |-
-|Fractured sandstone||0.0008 — 0.001
+|Fractured sandstone||0.0008-0.001
 |-
 |Alluvium, sand and gravel||0.017
 |-
-|Alluvium, poorly sorted sand and gravel||0.003 — 0.017
+|Alluvium, poorly sorted sand and gravel||0.003-0.017
 |-
-|Alluvium, sand and gravel||0.11 — 0.18
+|Alluvium, sand and gravel||0.11-0.18
 |-
-|Siltstone, sandstone, mudstone||0.01 — 0.05
+|Siltstone, sandstone, mudstone||0.01-0.05
 |}
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 A data mining analysis of 43 sites in California by Kulkarni et al. (2020) showed that on average 90% of the groundwater flow occurred in about 30% of cross sectional area perpendicular to groundwater flow.  These data provided “moderate (but not confirmatory) support for the&nbsp;mobile&nbsp;porosity&nbsp;concept.”<ref name="Kulkarni2020">Kulkarni, P.R., Godwin, W.R., Long, J.A., Newell, R.C., Newell, C.J., 2020. How much heterogeneity? Flow versus area from a big data perspective. Remediation 30(2), pp. 15-23. [https://doi.org/10.1002/rem.21639 DOI: 10.1002/rem.21639]  [//www.enviro.wiki/images/9/9b/Kulkarni2020.pdf Report.pdf]</ref>
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 ==References==

@@ Line 1: / Line 1: @@
-Groundwater migrates from areas of higher [[wikipedia: Hydraulic head | hydraulic head]] (a measure of pressure and gravitational energy) toward lower hydraulic head, transporting dissolved solutes through the combined processes of [[wikipedia: Advection | advection]] and [[wikipedia: Dispersion | dispersion]].  Advection refers to the bulk movement of solutes carried by flowing groundwater.  Dispersion refers to the spreading of the contaminant plume from highly concentrated areas to less concentrated areas.  In many groundwater transport models, solute transport is described by the advection-dispersion-reaction equation.
+Groundwater migrates from areas of higher [[wikipedia: Hydraulic head | hydraulic head]] toward lower hydraulic head, transporting dissolved solutes through the combined processes of [[wikipedia: Advection | advection]] and [[wikipedia: Dispersion | dispersion]].  Advection refers to the bulk movement of solutes carried by flowing groundwater.  Dispersion refers to the spreading of the contaminant plume from highly concentrated areas to less concentrated areas.  In many groundwater transport models, solute transport is described by the advection-dispersion-reaction equation in which dispersion coefficients can be calculated as the sum of molecular diffusion, mechanical dispersion, and macrodispersion.
 <div style="float:right;margin:0 0 2em 2em;">__TOC__</div>
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 ==Groundwater Flow==
 [[File:Newell-Article 1-Fig1r.JPG|thumbnail|left|400px|Figure 1. Hydraulic gradient (typically described in units of m/m or ft/ft) is the difference in hydraulic head from Point A to Point B (ΔH) divided by the distance between them (ΔL). In unconfined aquifers, the hydraulic gradient can also be described as the slope of the water table (Adapted from course notes developed by Dr. R.J. Mitchell, Western Washington University).]]
-Groundwater flows from areas of higher [[wikipedia: Hydraulic head | hydraulic head]] toward areas of lower hydraulic head (Figure 1). The rate of change (slope) of the hydraulic head is known as the hydraulic gradient. If groundwater is flowing and contains dissolved contaminants it can transport the contaminants from areas with high hydraulic head toward lower hydraulic head zones, or “downgradient”.
+Groundwater flows from areas of higher [[wikipedia: Hydraulic head | hydraulic head]] (a measure of pressure and gravitational energy) toward areas of lower hydraulic head (Figure 1). The rate of change (slope) of the hydraulic head is known as the hydraulic gradient. If groundwater is flowing and contains dissolved contaminants it can transport the contaminants from areas with high hydraulic head toward lower hydraulic head zones, or “downgradient”.
 ==Darcy's Law==
@@ Line 76: / Line 76: @@
 [[File:AdvectionFig2.PNG|400px|thumbnail|left|Figure 2. Hydraulic conductivity of selected rocks<ref>Heath, R.C., 1983. Basic ground-water hydrology, U.S. Geological Survey Water-Supply Paper 2220, 86 pgs. [//www.enviro.wiki/images/c/c4/Heath-1983-Basic_groundwater_hydrology_water_supply_paper.pdf Report pdf]</ref>.]]
-Darcy’s Law was first described by Henry Darcy (1856)<ref>Brown, G.O., 2002. Henry Darcy and the making of a law. Water Resources Research, 38(7), p. 1106. [https://doi.org/10.1029/2001wr000727 DOI: 10.1029/2001WR000727] [//www.enviro.wiki/images/4/40/Darcy2002.pdf Report.pdf]</ref> in a report regarding a water supply system he designed for the city of Dijon, France. Based on his experiments, he concluded that the amount of water flowing through a closed tube of sand (dark grey box in Figure 3) depends on (a) the change in the hydraulic head between the inlet and outlet of the tube, and (b) the hydraulic conductivity of the sand in the tube. Groundwater flows rapidly in the case of higher pressure (ΔH) or more permeable materials such as gravel or coarse sand, but flows slowly when the pressure is lower or the material is less permeable, such as fine sand or silt.
+Darcy’s Law was first described by Henry Darcy (1856)<ref>Brown, G.O., 2002. Henry Darcy and the making of a law. Water Resources Research, 38(7), p. 1106. [https://doi.org/10.1029/2001wr000727 DOI: 10.1029/2001WR000727] [//www.enviro.wiki/images/4/40/Darcy2002.pdf Report.pdf]</ref> in a report regarding a water supply system he designed for the city of Dijon, France. Based on his experiments, he concluded that the amount of water flowing through a closed tube of sand (dark grey box in Figure 3) depends on (a) the change in the hydraulic head between the inlet and outlet of the tube, and (b) the hydraulic conductivity of the sand in the tube. Groundwater flows rapidly in the case of higher pressure (ΔH) or more permeable materials such as gravel or coarse sand, but flows slowly when the pressure difference is lower or the material is less permeable, such as fine sand or silt.
 [[File:Newell-Article 1-Fig3..JPG|500px|thumbnail|right|Figure 3. Conceptual explanation of Darcy’s Law based on Darcy’s experiment (Adapted from course notes developed by Dr. R.J. Mitchell, Western Washington University).]]
-Since&nbsp;Darcy’s&nbsp;time,&nbsp;Darcy’s Law has been adapted to calculate the actual velocity that the groundwater is moving in units such as meters traveled per year. This quantity is called “interstitial velocity” or “seepage velocity” and is calculated by dividing the Darcy Velocity (flow per unit area) by the actual open pore area where groundwater is flowing, the “effective porosity”&nbsp;(Table 1):
+Since&nbsp;Darcy’s&nbsp;time,&nbsp;Darcy’s Law has been extended to develop a useful variation of Darcy's formula that is used to to calculate the actual velocity that the groundwater is moving in units such as meters traveled per year. This quantity is called “interstitial velocity” or “seepage velocity” and is calculated by dividing the Darcy Velocity (flow per unit area) by the actual open pore area where groundwater is flowing, the “effective porosity”&nbsp;(Table 1):
 [[File:Newell-Article 1-Equation 2r.jpg|400px]]
@@ Line 85: / Line 85: @@
 :Where:
 ::''V<sub>S</sub>'' = “interstitial velocity” or “seepage velocity” (units of length per time, such as m/sec)<br />
-::''V<sub>D</sub>'' = “Darcy Velocity”; describes groundwater flow as the volume of flow per unit area (units of length per time)<br />
+::''V<sub>D</sub>'' = “Darcy Velocity”; describes groundwater flow as the volume of flow per unit area per time (also units of length per time)<br />
-::''n<sub>e</sub>'' = Effective porosity (unitless)
+::''n<sub>e</sub>'' = Effective porosity - fraction of cross section available for groundwater flow (unitless)
-Effective porosity is smaller than total porosity. The difference is that total porosity includes some dead-end pores that do not support groundwater. Typically values for total and effective porosity are&nbsp;shown&nbsp;in&nbsp;Table&nbsp;1.
+Effective porosity is smaller than total porosity. The difference is that total porosity includes some dead-end pores that do not support groundwater. Typical values for total and effective porosity are&nbsp;shown&nbsp;in&nbsp;Table&nbsp;1.
 [[File:Newell-Article 1-Fig4.JPG|500px|thumbnail|left|Figure 4.  Difference between Darcy Velocity (also called Specific Discharge) and Seepage Velocity (also called Interstitial Velocity).]]
 ==Darcy Velocity and Seepage Velocity==
-In&nbsp;groundwater&nbsp;calculations, Darcy Velocity and Seepage Velocity are used for different purposes. For any calculation where the actual flow rate in units of volume per time (such as liters per day or gallons per minute) is involved, then the original Darcy Equation should be used (calculate ''V<sub>D</sub>'', Equation 1) without using effective porosity. When calculating solute travel time, then the seepage velocity calculation (''V<sub>S</sub>'', Equation 2) must be used and an estimate of effective porosity is required. Figure 4 illustrates the differences between Darcy Velocity and&nbsp;Seepage&nbsp;Velocity.
+In&nbsp;groundwater&nbsp;calculations, Darcy Velocity and Seepage Velocity are used for different purposes. For any calculation where the actual flow rate in units of volume per time (such as liters per day or gallons per minute) is involved, then the original Darcy Equation should be used (calculate ''V<sub>D</sub>'', Equation 1) without using effective porosity. When calculating solute travel time however, the seepage velocity calculation (''V<sub>S</sub>'', Equation 2) must be used and an estimate of effective porosity is required. Figure 4 illustrates the differences between Darcy Velocity and&nbsp;Seepage&nbsp;Velocity.
 ==Mobile Porosity==
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 A data mining analysis of 43 sites in California by Kulkarni et al. (2020) showed that on average 90% of the groundwater flow occurred in about 30% of cross sectional area perpendicular to groundwater flow.  These data provided “moderate (but not confirmatory) support for the&nbsp;mobile&nbsp;porosity&nbsp;concept.”<ref name="Kulkarni2020">Kulkarni, P.R., Godwin, W.R., Long, J.A., Newell, R.C., Newell, C.J., 2020. How much heterogeneity? Flow versus area from a big data perspective. Remediation 30(2), pp. 15-23. [https://doi.org/10.1002/rem.21639 DOI: 10.1002/rem.21639]  [//www.enviro.wiki/images/9/9b/Kulkarni2020.pdf Report.pdf]</ref>
 <br clear="left" />
 ==References==

@@ Line 76: / Line 76: @@
 [[File:AdvectionFig2.PNG|400px|thumbnail|left|Figure 2. Hydraulic conductivity of selected rocks<ref>Heath, R.C., 1983. Basic ground-water hydrology, U.S. Geological Survey Water-Supply Paper 2220, 86 pgs. [//www.enviro.wiki/images/c/c4/Heath-1983-Basic_groundwater_hydrology_water_supply_paper.pdf Report pdf]</ref>.]]
-Darcy’s Law was first described by Henry Darcy (1856)<ref>Brown, G.O., 2002. Henry Darcy and the making of a law. Water Resources Research, 38(7), p. 1106. [https://doi.org/10.1029/2001wr000727 DOI: 10.1029/2001WR000727] [//www.enviro.wiki/images/4/40/Darcy2002.pdf  Report.pdf]</ref> in a report regarding a water supply system he designed for the city of Dijon, France. Based on his experiments, he concluded that the amount of water flowing through a closed tube of sand (dark grey box in Figure 3) depends on (a) the change in the hydraulic head between the inlet and outlet of the tube, and (b) the hydraulic conductivity of the sand in the tube. Groundwater flows rapidly in the case of higher pressure (ΔH) or more permeable materials such as gravel or coarse sand, but flows slowly when the pressure is lower or the material is less permeable, such as fine sand or silt.
+Darcy’s Law was first described by Henry Darcy (1856)<ref>Brown, G.O., 2002. Henry Darcy and the making of a law. Water Resources Research, 38(7), p. 1106. [https://doi.org/10.1029/2001wr000727 DOI: 10.1029/2001WR000727] [//www.enviro.wiki/images/4/40/Darcy2002.pdf Report.pdf]</ref> in a report regarding a water supply system he designed for the city of Dijon, France. Based on his experiments, he concluded that the amount of water flowing through a closed tube of sand (dark grey box in Figure 3) depends on (a) the change in the hydraulic head between the inlet and outlet of the tube, and (b) the hydraulic conductivity of the sand in the tube. Groundwater flows rapidly in the case of higher pressure (ΔH) or more permeable materials such as gravel or coarse sand, but flows slowly when the pressure is lower or the material is less permeable, such as fine sand or silt.
 [[File:Newell-Article 1-Fig3..JPG|500px|thumbnail|right|Figure 3. Conceptual explanation of Darcy’s Law based on Darcy’s experiment (Adapted from course notes developed by Dr. R.J. Mitchell, Western Washington University).]]
@@ Line 133: / Line 133: @@
 |}
-Payne&nbsp;et&nbsp;al.&nbsp;(2009)&nbsp;reported the results from multiple short-term tracer tests conducted to aid the design of amendment injection systems<ref name="Payne2008" />. In these tests, the dissolved solutes were observed to migrate more rapidly through the aquifer than could be explained with typically reported values of ''n<sub>e</sub>''. They concluded that the heterogeneity of unconsolidated formations results in a relatively small area of an aquifer cross section carrying most of the water, and therefore solutes migrate more rapidly than expected. Based on these results, they recommend that a quantity called “mobile porosity” should be used in place of ''n<sub>e</sub>'' in equation 2 for calculating solute transport velocities. Based on 15 different tracer tests, typical values of mobile porosity range from 0.02 to 0.10 (Table 2).
+Payne&nbsp;et&nbsp;al.&nbsp;(2008)&nbsp;reported the results from multiple short-term tracer tests conducted to aid the design of amendment injection systems<ref name="Payne2008" />. In these tests, the dissolved solutes were observed to migrate more rapidly through the aquifer than could be explained with typically reported values of ''n<sub>e</sub>''. They concluded that the heterogeneity of unconsolidated formations results in a relatively small area of an aquifer cross section carrying most of the water, and therefore solutes migrate more rapidly than expected. Based on these results, they recommend that a quantity called “mobile porosity” should be used in place of ''n<sub>e</sub>'' in equation 2 for calculating solute transport velocities. Based on 15 different tracer tests, typical values of mobile porosity range from 0.02 to 0.10 (Table 2).
-A data mining analysis of 43 sites in California by Kulkarni et al. (2020) showed that on average 90% of the groundwater flow occurred in about 30% of cross sectional area perpendicular to groundwater flow.  These data provided “moderate (but not confirmatory) support for the&nbsp;mobile&nbsp;porosity&nbsp;concept.”<ref name="Kulkarni2020">Kulkarni, P.R., Godwin, W.R., Long, J.A., Newell, R.C., Newell, C.J., 2020. How much heterogeneity? Flow versus area from a big data perspective. Remediation 30(2), pp. 15-23. [https://doi.org/10.1002/rem.21639 DOI: 10.1002/rem.21639]  [//www.enviro.wiki/images/9/9b/Kulkarni2020.pdf  Report.pdf]</ref>
+A data mining analysis of 43 sites in California by Kulkarni et al. (2020) showed that on average 90% of the groundwater flow occurred in about 30% of cross sectional area perpendicular to groundwater flow.  These data provided “moderate (but not confirmatory) support for the&nbsp;mobile&nbsp;porosity&nbsp;concept.”<ref name="Kulkarni2020">Kulkarni, P.R., Godwin, W.R., Long, J.A., Newell, R.C., Newell, C.J., 2020. How much heterogeneity? Flow versus area from a big data perspective. Remediation 30(2), pp. 15-23. [https://doi.org/10.1002/rem.21639 DOI: 10.1002/rem.21639]  [//www.enviro.wiki/images/9/9b/Kulkarni2020.pdf Report.pdf]</ref>
 <br clear="left" />
 ==References==

@@ Line 91: / Line 91: @@
 ==Darcy Velocity and Seepage Velocity==
-In&nbsp;groundwater&nbsp;calculations, Darcy Velocity and Seepage Velocity are used for different purposes. For any calculation where the actual flow rate in units of volume per time (such as liters per day or gallons per minute) is involved, then the original Darcy Equation should be used (calculate ''V<sub>D</sub>''; Equation 1) without using effective porosity. When calculating solute travel time, then the seepage velocity calculation (''V<sub>S</sub>''; Equation 2) must be used and an estimate of effective porosity is required. Figure 4 illustrates the differences between Darcy Velocity and&nbsp;Seepage&nbsp;Velocity.
+In&nbsp;groundwater&nbsp;calculations, Darcy Velocity and Seepage Velocity are used for different purposes. For any calculation where the actual flow rate in units of volume per time (such as liters per day or gallons per minute) is involved, then the original Darcy Equation should be used (calculate ''V<sub>D</sub>'', Equation 1) without using effective porosity. When calculating solute travel time, then the seepage velocity calculation (''V<sub>S</sub>'', Equation 2) must be used and an estimate of effective porosity is required. Figure 4 illustrates the differences between Darcy Velocity and&nbsp;Seepage&nbsp;Velocity.
 ==Mobile Porosity==

← Older revision		Revision as of 14:33, 3 September 2020
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−	[[wikipedia: Advection \| Advection]] is the movement of groundwater through the subsurface due to pressure and gravitational energy. The combined processes of [[wikipedia: Advection \| advection]], [[wikipedia: Dispersion \| dispersion]], [[wikipedia: Diffusion \| diffusion]], sorption, and degradation control how long a contaminant plume will grow, remain stable, or shrink, as well as how easy or difficult it will be to remediate. The combined effects of these processes are represented in solute transport models with the advection-dispersion-reaction equation.	+	[[wikipedia: Advection \| Advection]] is the movement of groundwater through the subsurface due to variations in pressure and gravitational energy. The combined processes of [[wikipedia: Advection \| advection]], [[wikipedia: Dispersion \| dispersion]], [[wikipedia: Diffusion \| diffusion]], sorption, and degradation control how long a contaminant plume will grow, remain stable, or shrink, as well as how easy or difficult it will be to remediate. The combined effects of these processes are represented in solute transport models with the advection-dispersion-reaction equation.

	<div style="float:right;margin:0 0 2em 2em;">__TOC__</div>		<div style="float:right;margin:0 0 2em 2em;">__TOC__</div>