1. LAND SUBSIDENCE AND EARTH FISSURES IN ARIZONA Ching Sheng, Seah (ID 4147549) ‏ Melanie Poller (ID 2106795) ‏ Nhu Quynh Thi Nguyen(ID 4112793) ‏

2. Content Problems Geological Aspects Solutions

3. Earth fissure damage to residence in Nevada (photo by John Bell) ‏

4. Fissure gully near Picacho, Arizona (Photo by S.R. Anderson, USGS)

5. Fissure gully crossing below above- grade pipe at a mine facility in Nevada (photo by AMEC presented in 2004 ADOT workshop) ‏ Central Main Lateral Canal of the CAP crossing the Picacho earth fissure (photo by Michael Carpenter) ‏

6. SUMMARY OF THE PROBLEMS Increasing of all water use Warming climate RESULTS: Cracking of buildings Damage to roads, railway, storm sewers, underground pipelines,canals, etc. Cracks without advance warning

7. SUBSIDENCE Groundwater withdraw from aquifers in sedimentary basin Bowl-shaped depression EARTH FISSURES AND FISSURE GULLIES Cracks, seams or separations The sediment properties and stresses results in a subsurface rupture or separation Fissure Gullies: erosive forces move sediment downward

8. CRACK FORMATION Withdrawal of groundwater in the center Clay beds and other formations -thickest in the center - thinner toward the edges Overlying alluvium rotate (Herman Bouwer - Land Subsidence and Cracking Due to Ground – Water Depletion) SUBSIDENCE A B E F COMPRESSION D C

9. CRACK FORMATION Groundwater withdrawal - ridge - alluvial materials - thicker Linearly increasing subsidence Overlying slabs rotate (Herman Bouwer - Land Subsidence and Cracking Due to Ground – Water Depletion) COMPRESSIBLE BEDS COMPRESSION SUBSIDENCE CRACK

10. MONITORING AND POST CONSTRUCTION REMEDIAL ACTION Solution:

11. SUBSIDENCE MONITORING G eographic I nformation S ystem ( GIS ) + Close Range Photogrammetric System

12. G lobal P ositioning S ystem ( GPS ) Management tool S chedule I dentify E valuate

13. POST CONSTRUCTION REMEDIAL ACTION K eep W ater P ath A way from earth fissures Sealing of surface earth fissures + Diversion of Drainage Prevent erosion of surface flows -large gullies Solution: Clay + Bentonite mixed with soil + Soil cement (Good in treating Enlarged fissures) Filling with Gravel (less succesfull)

14. Using Cutoff Wall: Sheet Piling Cutoff Walls Water Path – Earth Fissure – deep – stability (Successful but hairline cracks developed) Geotextile Cutoff Barriers

15. THANK YOU!!