Hydrographic Surveys. The Key to Surface Water Planning and Management. Over 1000 INLAND Hydrographic Surveys Completed 5/25/2017

Transcription

1 Hydrographic Surveys The Key to Surface Water Planning and Management Over 1000 INLAND Hydrographic Surveys Completed 1

2 Hydrographic Surveys True or False? Marine and freshwater hydrographic surveys implement the same instruments, techniques and knowledge base? 2

3 Find the bottom Why Survey? 3

4 Why Survey? Why Survey? Why Survey? 4

5 Why Survey? Why Survey? Why Survey? 5

6 Why Survey? Why Survey? Why Survey? 6

7 Why worry about siltation? Increased flow Constricted flow Impeded flow Storm Water Encroachment Flooding/Safety Erosion Trash/debris collection Water quality degredation Invasive aquatic plant growth Decreased storage capacity Increased nutrient and toxin concentration Decreased Aesthetic Appeal Wildlife/Aquatic Life Recreation Property value degredation Permitting Government Intervention Health/safety/welfare of people How Do We Survey? 7

8 4 Components of Accuracy Survey Crew GPS Instruments (x,y) Sonar Instruments (z) Data processing protocol Missing component(s) = decreased accuracy Accuracy #1 - Survey Crew EXPERIENCE AND SKILL in HYDROGRAPHIC SURVEYING is MANDATORY Execute to meet client expectations Establish tide, setup and calibration Ground truthing Evaluate environmental factors that affect survey Transect establishment and tracking 8

9 Accuracy #2 - GPS Real Time Kinematic (RTK or RTK with VRS) 0.10 ft accuracy Differential GPS ft accuracy Location accuracy (x,y) can affect end product Accuracy #3 - Sonar Recreational Survey-grade Accuracy #4 Post Processing Survey-grade data reviewed point for point Recreational data generalized and averaged Check out the maps to see the difference. 9

10 Accuracy #4 Post Processing Hydrographic Survey Applications for Engineers, Public Works and Agency Planning, permitting and modeling Dredging planning, EOC and verification River-crossing utilities Renovation planning and execution Sedimentation monitoring (over time) Land use planning Construction and excavation Water volume calculations (strapping tables, capacity curves) Hydrographic Survey General Applications Aquatic vegetation mapping/control Safety, rescue and emergency use Fisheries management Boating and fishing Fisheries/wildlife habitat development 10

11 Hydrographic Survey Projects Urban storm water systems cities, developers, existing communities, dam safety Drinking water suppliers intakes, lagoons, sediment basins Safety and rescue operations fire/police Environmental consulting wetlands, lakes, wildlife Reserve studies projecting dredging needs Dredging verification In-house modeling, planning, permitting Potable Water Intakes Power Plant Lakes 11

12 Potable Water / Utilities 12

13 Pre/Post Dredge Analysis 13

14 Water Utilities Irrigation Planning Dredging Planning Verification Sedimentation Tracking 14

15 River and Stream Systems Watershed & Wetland Delineation More Specialized Hydrographic Surveys 15

16 Post Dredge Analysis Post Dredge Analysis Dredging Progress Report 16

17 River Pipeline Crossing Case Study Iowa DNR Client: Iowa DNR PROJECT: DNR lake dredging Scope: $6.5M based on studies performed before the project started Engineering company created a bathymetric map, but no one measured sediment RESULT: Calculations by the engineering firm were 1.5M CY short and the client, Iowa DNR had to settle with the dredging company and file a claim with the engineering firm s professional/e&o insurance company. Case Study Lake Association Client: Hidden Cove Lake Association PROJECT: Lake Dredging Scope: POA hired an engineering firm to develop a 5, 10 and 15 year phased dredging plan based on theoretical/modeled sediment accumulation. RESULT: POA purchased their own dredge, mobilized it, started dredging and discovered the sediment was not what the engineer modeled it as. We performed a hydrographic survey and learned that the estimated 100,000 CY of sediment was only 8,000 CY and could have been performed by a dredging contractor for $300,000. The POA had already spent $850,000 on engineering and a dredge. 17

18 Case Study Power Plant Ash Pond Case Study Precision Dredging/Excavation Plan the work, work the plan 18

19 Monitor, project and plan Monitor, project and plan Monitor, project and plan 19

20 Would you spend $3,000 To Save $30,000? Would you spend $20,000 To Save $200,000? First Step? 20

21 There are no substitutes or short cuts in hydrographics 21

22 Trent Lewis, FPC Senior Consultant Engineered Storm Water Solutions