USGS Methods of Collecting High Water Marks (HWMs)

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1 USGS Methods of Collecting High Water Marks (HWMs) A. Thomas Ruby III Supervisory Hydrologist Indiana-Kentucky Water Science Center U.S. Department of the Interior U.S. Geological Survey

2 Outline: Overview of Streamgages Why and when are high water marks collected? Types and documenting marks Location of high water marks High water mark field kits Flagging high water marks How are high water marks used: Examples with HWM collection in Kentucky

3 What is a Streamgage? A device that can provide continuous information on precipitation, surface water quantity (streamflow) and quality, or groundwater. Streamflow is a volume of water that passes a point on a stream per unit of time

4 USGS Monitoring Network Over 9,000 USGS streamflow-gaging stations across the Nation. Over 95% are real-time!

5 USGS Monitoring Network Kentucky Real-time Surface Water Sites Water Quality Sites Ground Water Sites Precipitation Gages Lake/Reservoir Gages 3 Super Gages

6 Surface Water Gages and installation

7 Data Collection Water Level Sensors Pressure System

8 USGS GOES near real-time Data Collection System GOES DOMSAT LRGS Field Station with Data Collection Platform (DCP) Data Access and Processing System (DAPS), Wallops Island, VA and EROS Data Center in Sioux Falls, SD National Water Information System (NWIS)

9 Data Collection The elevation of the water surface in the stream channel, known as a stage or gage height, can be used to determine the streamflow. When used in conjunction with velocity and cross-sectional area measurements, stage can be related to streamflow.

10 Data Collection Streamflow Measurements Wading Bridge

11 Data Collection Streamflow Measurements Manned Boat Remote Boat

12 Data Collection Compute streamflow from stage and cross-section area Q = VA A = w x

14 Data Processing Streamflow must be measured at all stages 100 Stage (ft) Discharge (cfs)

15 What happens when you can t get to the site at high stages to measure? Such as a Remote Area Flash Flood 100 Stage (ft) Discharge (cfs)

16 Scenario of Flash Flood Flatgap 2015, video, viewed, viewed 3, August 2015 Source: Resident of Flatgap, KY

17 It s time to collect High-Water Marks! Photograph, viewed 3, August 2015

18 Highwater marks (HWMs) HWMs are evidence of the highest stage of the flood Proper identification requires experience Get there quickly!

19 Highwater marks (HWMs) The need for speed marks can be highly perishable Rain can quickly degrade/destroy marks Important to locate and flag ASAP after a flood

20 The Why and When of HWMs Why: Calculation of an Indirect Measurement Model Calibration for Flood Inundation Maps Capture the high water event for future uses

21 What is an indirect measurement? It s a back calculation of streamflow! Three Factors: Physical characteristics of the channel Water-surface elevations at time of peak stage (HWM) Hydraulic factors Roughness coefficients

22 Types of hwms (definitions) Seedline: Seeds or other fine material left as a line on trees, bridge piers, buildings, and so forth. Cut line: The flow has cut a line into the ground surface at the water s edge. Wash line: Line on a bank below soil or organic matter has been cleared from a more erosionresistant surface.

23 Types of hwms (definitions con t) Debris or drift line: Sticks, trash, and other coarse material left on the ground at the edge of the water. Trash line: Sticks, trash, and other coarse material are left hanging in a tree or fence. Mud line or stain line: Sediment stain or general discoloration from water contact left as a line on trees, bridge piles, buildings, and so forth.

24 Location of HWMs On both banks (label as L-1, L-2, R-1, R-2, etc.) Get more than you think you ll need Through reach and a short distance upstream and downstream of reach Typically 2000 ft with.5 ft drop

25 Location of HWMs (cont.) Be aware of local effects, pile up, and drawdown

26 Rules of Thumb on HWMs Find low velocity areas for better quality away from main channel at the floodplain margin near water s edge close to ground Bushes can get bent down during flood and bend back up after flood creating an artificially high water surface

27 Rules of Thumb on HWMs (cont.) Fences or window screens are usually good sources Inside of buildings sometimes act as stilling wells (be certain level has equalized) Locate many; all are useful in interpretation of profile

28 HWMs (cont.) Other sources of HWM s Local residents Photographs Newspapers Photograph, viewed 3, August 2015 Photograph, viewed 3, August 2015

29 Setting High-Water Marks 1. Locate marks 2. Flag the marks with durable markers 3. Document the flagged marks 4. An elevation will need to be determined for the marks later for them to be useful.

30 HWMs (cont.) Most experienced person should act as rodman and locate highwater marks Avoid selecting marks which are too low Highwater marks should be flagged ASAP after a flood event before they disappear.

31 HWMs (cont.) Sometimes marks are best seen from a distance If possible, measure up or down from metal/concrete points while in the field, in lieu of permanent marks on private property (use driveways or window bottoms, etc).

32 HWMs (cont.) Type of mark e.g. mud line, seed line Location of mark lat/long, distance from a well defined point Type of flagging used e.g. nail through bottle cap Quality of the mark Miscellaneous important notes Landowner contact info Logistics/safety information Noting mark location on a map/site sketch is helpful Date stamped digital photo of marks is helpful

33 HWMs (cont.) Document marks in CLEAR note descriptions: Good seed line marked by nail on streamward side of a 12- inch diameter oak tree, 130 ft downstream from end of bridge, 5 ft from top left bank, 2.3 ft above the ground. Yellow flagging with HWM-L12 was used to identify the mark.

34 HWM forms (descriptions)

35 HWM forms (site sketch) HWM- R1 HWM- L1 HWM- L2 HWM- R2 HWM- L3 HWM- R3 HWM- L4

36 HWM forms (description and site sketch)

37 HWMs (cont.) Quality of HWM s Excellent -- within 0.02 ft Good -- within 0.05 ft Fair -- within 0.10 ft Poor -- within 0.20 ft PP -- greater than 0.20 ft

38 HWMs (seedlines) Excellent seedline on another 12-inch tree

39 HWMs (seedlines) Good seedline on large 30-inch tree (fewer particles)

40 HWMs (seedlines) Fair to poor seedline on 10- inch tree. (even less particles)

41 HWMs (seedlines) Good to excellent seedline on fencepost

42 HWMs (seedlines) Excellent seedline just inside a doorway. (note person is measuring up from a permanent surface)

43 HWMs (seedlines) Excellent seedline on outside of building.

44 HWMs (stain lines) Good stain line on outside of building.

45 HWMs (stain lines) Fair to poor stain line on trees and bushes.

46 HWMs (stain lines) Good stain line on outside of building.

47 HWMs (stain lines) Good stain line on wooden steps.

48 HWMs (debris or drift lines) Fair drift line 30 ft from lowwater channel

49 HWMs (debris or drift lines) Close-up of same drift line as in previous photo. Use ground elevation at bankward side of debris (not top of debris)

50 HWMs (debris or drift lines) An equally apparent but poor drift line Avoid this type. Due to pile-up, accuracy may be only to the nearest foot.

51 HWMs (trash lines) Good trash line on chain link fence (hard to miss!)

52 HWMs (trash lines) Poor trash line on chain link fence Obviously, the water surface did not follow this line

53 HWMs (trash lines) Very poor trash line in bank vegetation These bushes bend over in the velocity and pop up, creating a mark that is simply too high

54 HWMs (wash lines) Poor wash line (no organic debris below high water)

55 You Found the HWMs Now What?

56 Flagging HWMs Use a durable marker to note water surface Nail/cap Surveyor s tape Paint mark Wooden stake Chiseled square or line in concrete/rock IMPORTANT make sure you get permission of property owners before flagging marks!

57 Basic HWM Field Kit Nails HWM disks, washers, bottle caps Wooden stakes Paint crayon spray paint Surveying flagging tape high vis. Hammer Chisel Small dry-erase board with dryerase markers Container canvas bag, toolbox, bucket with tool pouch Easily put together for <$50

58 Kit additions Hand level 100 ft. tape Range Finder Hand-held GPS Digital Camera Safety/comfort items e.g. insect repellant, ivy wipes, sunscreen, safety glasses

59 Marking Examples

61 Chiseled square on sidewalk Painted Line on Boat Ramp

63 Get at least 2 pictures of each HWM One with background in frame One up close with description visible

64 How HWMs are Used Examples with HWM collection in Kentucky

65 FEMA Collection/Documentation Field lead 5 Teams of 2 Office support 69 total river miles 6 different streams 9 counties

69 Collection and Documentation on the fly

70 Collection and Documentation on the fly

71 Collection and Documentation on the fly

72 Flood Inundation Maps

73 Final Products

75 In Conclusion: Always look a little higher make sure you are not marking a lower, secondary peak which is common Setting multiple marks can be advantageous, also try to get them on both sides of the channel Get the permission before entering!! A HWM should represent the water surface in relatively still water And Remember:

76 Some HWM s wash away in the rain and others just melt!

77 Still a few just get up and walk away!

78 Questions -?? I wish I had USGS HWM Kit! Thomas Ruby aruby@usgs.gov

Duncan Hastie, P.E. Dewberry

FEMA s Riverine High Water Marks for Atlanta s September 2009 Flood Event Duncan Hastie, P.E. Dewberry Background High Water Mark Recovery Performed Through FEMA s Hazard Mitigation Technical Assistance