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Groundwater 102

Groundwater 102. How does development affect groundwater levels?. June 7 th 2007. K (feet/day). 100. 100. Groundwater flow. K (feet/day). ???. 100. Groundwater flow. Let’s dig a 4 foot deep drainage trench. Groundwater flow?. How about a 4 foot deep concrete wall?. Groundwater flow?.

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Groundwater 102

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  1. Groundwater 102 How does development affect groundwater levels?

  2. June 7th 2007

  3. K (feet/day) 100 100 Groundwater flow

  4. K (feet/day) ??? 100 Groundwater flow

  5. Let’s dig a 4 foot deep drainage trench Groundwater flow?

  6. How about a 4 foot deep concrete wall? Groundwater flow?

  7. To model this we would need to know: How much water is there? What is its direction of flow? What is its rate of flow (gradient + K) Groundwater flow?

  8. Foundations and cutoff walls: In aquifers, foundations can significantly affect groundwater flow patterns, producing both damming and funneling features.

  9. The impacts of urbanization on groundwater systems and recharge John M. Sharp, Jr. The network (or reticulation) of water mains, sewer lines, electrical and telephone conduits, storm drains/sewers, subways, and other sub- surface systems is one of the major alterations to the hydrogeology of an urban area. Developer’s Report The most important conclusion of this study is that the proposed housing development on the Hogan-Pancost Property can only lead to a decrease in sump pumping in nearby residences.

  10. Professor John M Sharp Carlton Professor of Geology, Department of Geological Sciences, Jackson School of Geosciences PUBLICATIONS: Dr. Sharp has published over 300 journal articles and abstracts, over 15 monographs/book chapters, and over 40 book reviews. He has given many invited research presentations, locally, nationally, and internationally. President, Geological Society of America (2007) Member, Founders Award Committee, American Institute of Hydrology (2004) Treasurer, International Association of Hydrogeologists (2004 - 2008) President, US National Committee, International Association of Hydrogeologists (2004 - 2008)

  11. EFFECTS OF URBANIZATION ON GROUNDWATER SYSTEMS J. N. Krothe, B. Garcia-Fresca, and J. M. Sharp Urbanization has dramatic effects on groundwater systems with ramifications for water management. Increases in permeability within the utility systems are documented up to 10 orders of magnitude greater than the natural materials, although 2 to 4 orders are more common. Prediction of groundwater flow and contaminant transport is difficult; and remediation in such systems can be problematic. Developer’s Groundwater Response Letter - Fall 2011 It is not possible for the development on Hogan-Pancost property to significantly influence the local ground water level because the lateral extent of the underlying ground water is so extensive and the property represents only a small fraction (0.03%) of the total watershed area. The property owners can only control on-site recharge. (emph added)

  12. Construction dewatering and groundwater control: new methods and applicationsBy J. Patrick Powers, Christine J. Herridge, Arthur B. Corwin, Paul C. Schmall

  13. Another example of causing a rise in groundwater in groundwater level at a regional scale can be from fields of piled earth, made during the total building up of microrayons. In the pile field zone, the ground is so compressed that its filtration properties decrease almost by an order. Thus, considerable backing-up due to the damming effect of a pile field occurs and a vast area of flooding upstream

  14. 8-5-12 Standards for Repairs and Restoration of Pavement or Sidewalks. (b) Flowable Fill Required: Flowable fill backfill material, or an equivalent backfill material approved by the city manager that provides an incompressible, settlement-free, stable surface satisfying the design and construction standards adopted by the city, shall be used to restore all trenches that have been excavated in the paved or traveled portion of any public street or alley.

  15. Developer Soils Report Prior to the over-lot grading, all organics and any loose fill should be stripped from the site. The stripped surface should then be scarified and compacted to at least 90% of maximum dry density for landscaped areas and to at least 95% of maximum dry density for any areas which are to be paved with concrete or asphalt. If any fill is required beneath a slab, we recommend using a granular non-expansive structural fill compacted in 9” maximum lifts to the standard referenced above. Mechanically compact all fill around the buildings, including the backfill.

  16. Lateral groundwater flow Soil test pit profile - water at 2 feet below surface Foundations extend 4 feet below surface Which causes a damming effect raising groundwater levels

  17. 12 homes along south side spanning 900 feet = 780 linear feet of foundation wall

  18. Groundwater 102 How does development affect groundwater levels? In many many complicated ways

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