Hydraulic_Memo.pdf

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Hydraulic memo_FINAL.docx

Form FHWA-201 U.S. DEPARTMENT OF TRANSPORTATION (Rev. 11-67) FEDERAL HIGHWAY ADMINISTRATION

MINUTE - MEMO

Use this form in lieu of transmittal slips within Dept. of Trans. when message comment is to be retained as file material. Do not prepare carbons. Not to be used in lieu of form FHWA-121 for informal correspondence.

Subject: Project FW OCBA T302(1) – Hydraulic Design Memo

TO MESSAGE/COMMENT FROM/DATE

Libby Gress Hydraulics Team Leader

Overview

Occoquan Bay National Wildlife Reserve is located in the Town of Woodbridge in Prince William County, Virginia. Deephole Point Road runs along the coast of Occoquan Bay which is part of the tidally influenced Potomac River. The project location is between the intersections of Fox Rd and Easy Rd, and has four (4) culvert crossing locations in this section. The existing culverts are Triple (3x) 24-inch diameter corrugated metal pipes (CMP) with concrete headwalls.

Additionally, the project also includes a culvert crossing on Easy Road.

This crossing consists of two (2) 36-inch reinforced concrete culverts (RCP) with no headwalls.

The purpose of this project is to replace and upgrade the existing culverts to minimize overtopping of the road in the high tide events and provide more tidal exchange with the wetlands behind the road.

Hydrologic Data

There are 4 drainage basins for the culverts within the project limits.

Sites 1, 2 and 3 each have separate basins, and sites 4 and 5 are linked to the same basin. Two distinct blue line streams run through the Reserve, at Site 2 and Site 4. The size of these basins for these two sites are 35 acres and 640 acres (1 sq mi), respectively. The drainage basins for sites 1 and 3 are less that these two sites (8 acres and 26 acres) and water from the wetlands, which comprise these basins, are interconnected to the other two sites.

While the drainage area for Site 4 is significantly larger, the hydrology of this site has been altered over time by beaver dams and tidal deposits. Prior to the creation of the Refuge, the area was an Army installation. Mapping from this period, as well as current mapping shows two blue line streams entering the drainage basin upstream of Site 5. This area is mostly open water wetlands. There is an additional discharge point for the basin, not entirely clear on the mapping, on Deephole Point Rd east of Site 4. During Hurricane Sandy (2012) the culverts at this location were washed out. It is not known what culverts existed prior to the storm but it is assumed they were the same as the others on Deephole Point and were triple-24” culverts. The replacement culverts are 3 large culverts (48” or larger).

It was observed on site in October 2016 and June 2017 that most the discharge from the basin occurs through this site. Additionally, survey indicates that invert elevations for site 5 are approximately 6 inches to 1 foot higher than the invert elevations at the discharge at Deephole Point Rd. The Refuge managers also stated they have not seen the

James Ruppert Lead Designer

7/7/16

Through

Alazar Feleke Highway Design Manager

Page 2 of 5 Pages culverts at site 5 overtopped. It can be assumed that the culverts at site 5 act as relief culverts for the basin during high water events from the upstream basin.

Since the purpose of this project is not to study the storage attenuation of the basin, a qualitative approach is used to estimate the flow from the basin at site 5. Site 4 is situated downstream of Site 5 and will only ever see the flow from Site 5. Given the hydraulic changes to the other discharge point and the relief nature of the culverts at site 5, it is assumed the peak flow through site 5 is roughly equal to the flow through site 2.

Drainage basin characteristics were generated from the STREAMSTATS website run by the US Geologic Service (USGS).

The STREAMSTATS program utilizes digitized USGS topographic maps to delineate watersheds from associated blue line streams shown on the map. The peak discharge for Site 2 was used at the basis for all 5 culvert locations. Peak discharges were computed using rational method as the drainage area is well below the lower boundary for utilizing the regression routing in STREAMSTATS.

Rational Method Peak Discharges

Drainage Area 0.053 sq mi (35 ac)

Design Discharge (Q25) 24 cfs

Check Dishcharge (Q100) 31 cfs

Ordinary High Water (Q2) 13 cfs

Tidal Data

Tidal Elevations for Woodbridge, VA were calculated by applying time difference and height ratios to the predictions listed for the closest reference station, Indian Head, MD, and assuming the predicted tides equal. This station is a subordinate station and is referenced to the main control station at Washington, DC. The procedure for correlating the tidal data is presented in the Virginia Department of Transportation (VDOT) Drainage Manual, Chapters 12 and 13. Additional reference to subordinate stations can be found in the Maine DOT Bridge Design Guide, Chapter 2. Below is a summary of the tidal elevations for Woodbridge, VA:

Mean Lower Low Water -0.87 ft Mean Low Water -0.77 ft Mean Tide Level 0.15 ft Mean High Water 1.08 ft Mean Higher High Water 1.63 ft 2016 Predicted High Tide 1.6 ft

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Hydraulic Data

Hydraulic analysis of the existing culverts was performed with the FHWA program HY-8 using the hydrologic and tidal data noted above.

The headwater elevations were computed using the tailwater at MHW to maximize the headwater elevations. The discharge velocities were computed with the tailwater at MLW to maximize discharge velocity.

The State of Virginia requires that all culverts placed in streams and at road crossings between two bodies of water be countersunk to maintain low flow characteristics and facilitate aquatic organism passage. All pipes greater than 24 inches in diameter are required to have both the inlet and outlet ends of the pipe buried a minimum of 6 inches below the natural streambed. The HY-8 program incorporates an embedment function to address the countersinking.

Three alternative were analyzed for selecting the option which gives the greatest benefit to the Refuge. For clarity, only replacement with 36” pipes of the same material as existing are shown. All other options with a greater waterway opening provide better tidal exchange and further reduce exit velocities during low tide. A chart detailing the waterway openings of the various options is included in the Appendix.

Below is a summary of the results:

Existing (3x 24” CMP)

Proposed (3x 36” CMP)

MHW 1.08 ft HW Elev @ Q2 1.16 ft 1.08 ft

HW Elev @ Q25 1.36 ft 1.08 ft

HW Elev @ Q100 1.51 ft 1.09 ft

Velocity @ Q25 5.12 ft/s 1.03 ft/s

Velocity @ Q100 5.53 ft/s 1.27 ft/s Freeboard @2016 Predicted Tide

0.4 ft 1.65 ft

These results show the headwater elevation, for the existing configuration, at Q2 and Q25 is only 0.08 feet (1 inch) and 0.28 feet (3 inches) higher than the tailwater elevation (MHW), respectively. For the proposed configuration, the headwater elevations match the tailwater. Based on this finding, it can be concluded that the headwater depths are governed by the tidal elevations. Therefore, the hydraulics of the replacement culverts are based on the tide information rather than stream flow from the upstream wetland area.

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Correlation between Predicted and Observed Tidal Elevations

During initial project scoping in 2014, and reiterated during a site visit October 6, 2016, the refuge manager for the Fish and Wildlife Service (FWS) provided information that the road at the culvert locations is inundated by approximately 1 foot, monthly. This information would place the high tide at an approximate elevation of 3 feet. The October site visit was coincidently at high tide for that day and we observed the high tide at an elevation of approximately 1.9 feet. A review of the water levels for October 6, 2016 at the Washington D.C. station shows that the recorded levels were 1.1 feet higher than predicted. Using the prediction methodology previously mentioned, the predicted elevation for that day is 1.15 feet, or 2.25 feet correcting to the reported elevation. The discrepancy between the observed and predicted water levels is well within the standard of error for the prediction, especially since the predicted water levels are taken from a subordinate station.

Proposed Structure

After investigation, the culverts along the Deephole Point Road do not act as drainage culverts for the wetland area upland of the road but rather as a source of tidal exchange. While the existing pipes are adequately sized to handle the upland drainage during low tide events, increasing the size of the culverts would allow better exchange of tidal water and less restriction to higher tide events. It is recommended that the replacement culverts be sized based on the high tide information with minimal consideration given to stream flow.

Using current construction cost data, a comparison was performed of all Options considered for replacement. This comparison can be found in the Appendix.

Considering all the factors outlined above, we recommend the replacement culverts be open bottom concrete arch structures with the dimensions of 12’ Span x 4’ Rise. This structure provides the largest waterway opening of all structures analyzed and provides the greatest benefit to the Refuge. The increased waterway will reduce exit velocities at low tide, promote more efficient exchange of water between the Bay and the wetlands inside the Refuge, and decrease the likelihood of clogging in the structure due to debris and driftwood.

Additionally, considering the FWS request to prevent inundation during tidal events, the road will be raised at the culvert location to an elevation of 3.25 feet. This elevation is higher than any of the predicted tides, providing additional freeboard during extreme high tide events. Riprap will be placed at the edges of the headwalls to protect against scour

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Scour Countermeasures

The existing culverts show some very minor signs of scour, mainly at the ends of the headwalls. The proposed concrete arch will allow for more efficient exchange of tidal waters, will increase the hydraulic opening, and will decrease the water velocities and scour potential.

Riprap slope protection will be provided as an additional scour countermeasure extending out from the ends of the headwalls and tying back in to the existing riprap slope protection. As an added measure of protection, riprap will be placed at the outlet of the culverts, in the bay, to prevent any scour from undermining the headwalls during tidal exchange.

Conclusion

The proposed concrete arch structure will improve the hydraulics and tidal exchange along Deephole Point Rd. By selecting the concrete arch, the hydraulic opening is roughly 3.5 times larger than the existing opening. By raising the road slightly at the culvert openings, the road will no longer be inundated during high tide events and will provide extra protection during large storm events. The increased size of the proposed concrete arch and the decreased velocities at the site indicate that there is low scour potential and that riprap slope protection will be an adequate scour countermeasure.

ATTACHMENTS

Site #2-Hydrology

Drainage Area Map Rational Method Output

Site #4-Hydrology Drainage Area Map Streamstats Output

Tidal Information Washington DC (reference station) Indian Head, MD (subordinate station)

HY8 Output EX 24” w/ TW @ MHW / MLW PROP Analysis w/ TW @ MHW / MLW o Triple 36” CMP o Double 4’ span x 3‘ rise box culvert o Double 60” span x 38” rise Elliptical pipes

Comparison Tables Waterway Comparison Cost Comparison

SITE #2 – HYDROLOGY

Basin Characteristics Ungaged Site Report

Date: Tues Oct 18, 2016 12:45:11 PM GMT‐4 Study Area: Virginia NAD 1983 Latitude: 38.6373 ( 38 38 14) NAD 1983 Longitude: ‐77.236 (‐77 14 10)

Label Value Units Definition

DRNAREA 0.0533 square miles Area that drains to a point on a stream ELEV 11.78 feet Mean Basin Elevation ELEVMAX 23.46 feet Maximum basin elevation MINBELEV 0.23 feet Minimum basin elevation RELIEF 23.2 feet Maximum ‐ minimum elevation PRECIP 42.951 inches Mean Annual Precipitation

I24H2Y 3.122 inches Maximum 24‐hour precipitation that occurs on average once in 2 years ‐ Equivalent to precitation intensity index

LC01IMP 0.25 percent Average percentage of impervious land cover from NLCD 2001

LC06IMP 0.25 percent Average percentage of impervious area determined from NLCD 2006 impervious dataset

LC11IMP 0 percent Average percentage of impervious area determined from NLCD 2011 impervious dataset

LC01DEV 3.69 percent Percentage of land‐use from NLCD 2001 classes 21‐24 LC06DEV 2.68 percent Percentage of land‐use from NLCD 2006 classes 21‐24 LC11DEV 0 percent Percentage of developed (urban) land from NLCD 2011 classes 21‐24 CB01DEV 4.92 percent Percent developed from 2001 Chesapeake Bay land cover dataset CB06DEV 4.92 percent Percent developed 2006 Chesapeake Bay land cover dataset LC01WATER 0 percent Percentage of open water, class 11, from NLCD 2001 LC06WATER 0 percent Percent of open water, class 11, from NLCD 2006 LC11WATER 0 percent Percent of open water, class 11, from NLCD 2011 CB01WATER 0 percent Percent open water from 2001 Chesapeake Bay land cover dataset CB06WATER 0 percent Percent water from 2006 Chesapeake Bay land cover dataset LC01WETLND 30.05 percent Percentage of wetlands, classes 90 and 95, from NLCD 2001 LC06WETLND 28.31 percent Percentage of wetlands, classes 90 and 95, from NLCD 2006 LC11WETLND 26.43 percent Percentage of wetlands, classes 90 and 95, from NLCD 2011 CB01WETLND 25.2 percent Percent wetlands 2001 Chesapeake Bay land cover dataset CB06WETLND 26.29 percent Percent wetlands from 2006 Chesapeake Bay land cover dataset

LC01FORSHB 1.23 percent Percentage of forests and shrub lands, classes 41 to 52, from NLCD

LC06FORSHB 2.32 percent Percentage of forests and shrub lands, classes 41 to 52, from NLCD

LC11FORSHB 17.45 percent Percentage of forests and shrub lands, classes 41 to 52, from NLCD

CB01FORSHB 2.75 percent Percent forests and shrub lands from 2001 Chesapeake Bay land cover dataset

CB06FORSHB 3.55 percent Percent forests and shrub lands from 2006 Chesapeake Bay land cover dataset

LC01CRPHAY 65.03 percent Percentage of cultivated crops and hay, classes 81 and 82, from NLCD

LC06CRPHAY 66.69 percent Percentage of cultivated crops and hay, classes 81 and 82, from NLCD

LC11CRPHAY 56.12 percent Percentage of cultivated crops and hay, classes 81 and 82, from NLCD

StreamStats Version 3.0 http://streamstats.usgs.gov/

CB01CRPHAY 65.24 percent Percent cultivated crops and hay from 2001 Chesapeake Bay land cover dataset

CB06CRPHAY 65.24 percent Percent cultivated crops and hay from 2006 Chesapeake Bay land cover dataset

LC01HERB 0 percent Percentage of herbaceous upland from NLCD 2001 class 71 LC06GRASS 0 percent Percentage of grassland from NLCD 2006 class 71 LC11GRASS 0 percent Percentage of grassland from NLCD 2011 class 71 CB01HERB 0 percent Percent herbaceous from 2001 Chesapeake Bay land cover dataset CB06HERB 0 percent Percent herbaceous from 2006 Chesapeake Bay land cover dataset LC01BARE 0 percent Percentage of area barren land, NLCD 2001 category 31 LC06BARE 0 percent Percentage of barren from NLCD 2006 class 31 LC11BARE 0 percent Percentage of barren from NLCD 2011 class 31 CB01BARE 0 percent Percent barren from 2001 Chesapeake Bay land cover dataset CB06BARE 0 percent Percent barren from 2006 Chesapeake Bay land cover dataset

BRMETA 0 percent Percent area of metamorphic rocks within the Blue Ridge Physiographic Region

CPSED 100 percent Percent area of sedimentary rockswithin the Coastal Plain Physiographic Region

PDIGMET 0 percent Percent area of igneous and metamorphic within the Piedmont Physiographic Region

MESZOIC 0 percent Percent of area within the Mesozoic Basins

VRPLSLC 0 percent Percent of area of siliciclastic rocks witin the Valley and Ridge or Appalachian Plateau Physiographic Regions

VRCARB 0 percent Percent of area of carbonate rocks within the Valley and Ridge Physiographic Region

STATSWATCP 0.12 in per in Available water capacity of the top 60 inches of soil ‐ determined from STATSGO data

STATSPERM 3.21 inches per hour

Area‐weighted average soil permeability from NRCS STATSGO database

STATSGODEP 72 inches Area‐weighted average soil depth from NRCS STATSGO database STATSCLAY10 0 percent Percentage of soils with less than 10 percent clay from STATSGO

STATSCLY20 0 percent Percentage of soils with greater than 10 percent and less than or equal to 20 percent clay from STATSGO

STATSCLY30 100 percent Percentage of soils with greater than 20 percent and less than or equal to 30 percent clay from STATSGO

STATSCLY40 0 percent Percentage of soils with greater than 30 percent and less than or equal to 40 percent clay from STATSGO

STATSCLY50 0 percent Percentage of soils with greater than 40 percent and less than or equal to 50 percent clay from STATSGO

STATSCLY60 0 percent Percentage of soils with greater than 50 percent and less than or equal to 60 percent clay from STATSGO

STATSOM0_5 100 percent Percentage of soils with less than 0.5 percent organic matter from

STATSGO

STATSOM2_6 0 percent Percentage of soils with greater than 0.50 percent and less than or equal to 2.60 percent organic matter from STATSGO

STATSOM7_3 0 percent Percentage of soils with greater than 2.6 percent and less than or equal to 7.3 percent organic matter from STATSGO

STATOM19_8 0 percent Percentage of soils with greater than 7.3 percent and less than or equal to 19.8 percent organic matter from STATSGO

STATOM55_7 0 percent Percentage of soils with greater than 19.8 percent and less than or equal to 55.7 percent organic matter from STATSGO

LFREGNO 1544 undefined PKREGNO 1550 undefined DEVNLCD01 3.69 percent Percentage of land‐use categories 21‐24 from NLCD 2001

HYDRAULIC TOOLBOX SUMMARY DATA

PROJECT:

LOCATION: SITE 2 CULVERT ON DEEPHOLE POINT RD

DATE: 7/7/2017

CONDITION: EXISTING PROPOSED *NO CHANGE TO DRAINAGE AREA DURING CONSTRUCTION

COMPUTED: JWR

Length Top Elev. Bottom Elev. Slope Manning's n k Tc (min) Sheet Flow 100 23.5 22.8 0.007 0.24 22 Shallow Concentrated Flow 1500 22.8 12.3 0.007 0.2 45.3 Channel Flow 1700 12.3 0.4 0.007 0.033 13.3

C Value 0.3 assume all unimproved area 80.6 Area 35 acres i (in/hr) Q (cfs)

2yr 1.2 12.8

25yr 2.26 24

100yr 2.86 30.3

OCBA T302(1)

TIME OF CONCENTRATION

SITE #4 – HYDROLOGY

Basin Characteristics Ungaged Site Report

Date: Tues Oct 18, 2016 10:47:26 AM GMT‐4 Study Area: Virginia NAD 1983 Latitude: 38.6372 ( 38 38 14) NAD 1983 Longitude: ‐77.2307 (‐77 13 51)

Label Value Units Definition

DRNAREA 1 square miles Area that drains to a point on a stream ELEV 22.03 feet Mean Basin Elevation ELEVMAX 90.13 feet Maximum basin elevation MINBELEV 0 feet Minimum basin elevation RELIEF 90.1 feet Maximum ‐ minimum elevation PRECIP 42.981 inches Mean Annual Precipitation

I24H2Y 3.119 inches Maximum 24‐hour precipitation that occurs on average once in 2 years ‐ Equivalent to precitation intensity index

LC01IMP 20.09 percent Average percentage of impervious land cover from NLCD 2001

LC06IMP 21.5 percent Average percentage of impervious area determined from NLCD 2006 impervious dataset

LC11IMP 20.5 percent Average percentage of impervious area determined from NLCD 2011 impervious dataset

LC01DEV 55.55 percent Percentage of land‐use from NLCD 2001 classes 21‐24 LC06DEV 57.25 percent Percentage of land‐use from NLCD 2006 classes 21‐24 LC11DEV 47.3 percent Percentage of developed (urban) land from NLCD 2011 classes 21‐24 CB01DEV 56.37 percent Percent developed from 2001 Chesapeake Bay land cover dataset CB06DEV 56.37 percent Percent developed 2006 Chesapeake Bay land cover dataset LC01WATER 0.17 percent Percentage of open water, class 11, from NLCD 2001 LC06WATER 0.17 percent Percent of open water, class 11, from NLCD 2006 LC11WATER 0.17 percent Percent of open water, class 11, from NLCD 2011 CB01WATER 0.17 percent Percent open water from 2001 Chesapeake Bay land cover dataset CB06WATER 0.17 percent Percent water from 2006 Chesapeake Bay land cover dataset LC01WETLND 16.85 percent Percentage of wetlands, classes 90 and 95, from NLCD 2001 LC06WETLND 16.61 percent Percentage of wetlands, classes 90 and 95, from NLCD 2006 LC11WETLND 18.47 percent Percentage of wetlands, classes 90 and 95, from NLCD 2011 CB01WETLND 15.31 percent Percent wetlands 2001 Chesapeake Bay land cover dataset CB06WETLND 15.63 percent Percent wetlands from 2006 Chesapeake Bay land cover dataset

LC01FORSHB 7.78 percent Percentage of forests and shrub lands, classes 41 to 52, from NLCD

LC06FORSHB 6.86 percent Percentage of forests and shrub lands, classes 41 to 52, from NLCD

LC11FORSHB 4.35 percent Percentage of forests and shrub lands, classes 41 to 52, from NLCD

CB01FORSHB 9.31 percent Percent forests and shrub lands from 2001 Chesapeake Bay land cover dataset

CB06FORSHB 9.53 percent Percent forests and shrub lands from 2006 Chesapeake Bay land cover dataset

LC01CRPHAY 19.29 percent Percentage of cultivated crops and hay, classes 81 and 82, from NLCD

LC06CRPHAY 18.77 percent Percentage of cultivated crops and hay, classes 81 and 82, from NLCD

LC11CRPHAY 26.51 percent Percentage of cultivated crops and hay, classes 81 and 82, from NLCD

CB01CRPHAY 17.48 percent Percent cultivated crops and hay from 2001 Chesapeake Bay land cover dataset

CB06CRPHAY 17.72 percent Percent cultivated crops and hay from 2006 Chesapeake Bay land cover dataset

LC01HERB 0.31 percent Percentage of herbaceous upland from NLCD 2001 class 71 LC06GRASS 0.3 percent Percentage of grassland from NLCD 2006 class 71 LC11GRASS 3.14 percent Percentage of grassland from NLCD 2011 class 71 CB01HERB 0.94 percent Percent herbaceous from 2001 Chesapeake Bay land cover dataset CB06HERB 0.8 percent Percent herbaceous from 2006 Chesapeake Bay land cover dataset LC01BARE 0.04 percent Percentage of area barren land, NLCD 2001 category 31 LC06BARE 0.03 percent Percentage of barren from NLCD 2006 class 31 LC11BARE 0.02 percent Percentage of barren from NLCD 2011 class 31 CB01BARE 0 percent Percent barren from 2001 Chesapeake Bay land cover dataset CB06BARE 0 percent Percent barren from 2006 Chesapeake Bay land cover dataset

BRMETA 0 percent Percent area of metamorphic rocks within the Blue Ridge Physiographic Region

CPSED 99.95 percent Percent area of sedimentary rockswithin the Coastal Plain Physiographic Region

PDIGMET 0 percent Percent area of igneous and metamorphic within the Piedmont Physiographic Region

MESZOIC 0 percent Percent of area within the Mesozoic Basins

VRPLSLC 0 percent Percent of area of siliciclastic rocks witin the Valley and Ridge or Appalachian Plateau Physiographic Regions

VRCARB 0 percent Percent of area of carbonate rocks within the Valley and Ridge Physiographic Region

STATSWATCP 0.12 in per in Available water capacity of the top 60 inches of soil ‐ determined from STATSGO data

STATSPERM 3.21 inches per hour

Area‐weighted average soil permeability from NRCS STATSGO database

STATSGODEP 72 inches Area‐weighted average soil depth from NRCS STATSGO database STATSCLAY10 0 percent Percentage of soils with less than 10 percent clay from STATSGO

STATSCLY20 0 percent Percentage of soils with greater than 10 percent and less than or equal to 20 percent clay from STATSGO

STATSCLY30 100 percent Percentage of soils with greater than 20 percent and less than or equal to 30 percent clay from STATSGO

STATSCLY40 0 percent Percentage of soils with greater than 30 percent and less than or equal to 40 percent clay from STATSGO

STATSCLY50 0 percent Percentage of soils with greater than 40 percent and less than or equal to 50 percent clay from STATSGO

STATSCLY60 0 percent Percentage of soils with greater than 50 percent and less than or equal to 60 percent clay from STATSGO

STATSOM0_5 100 percent Percentage of soils with less than 0.5 percent organic matter from

STATSGO

STATSOM2_6 0 percent Percentage of soils with greater than 0.50 percent and less than or equal to 2.60 percent organic matter from STATSGO

STATSOM7_3 0 percent Percentage of soils with greater than 2.6 percent and less than or equal to 7.3 percent organic matter from STATSGO

STATOM19_8 0 percent Percentage of soils with greater than 7.3 percent and less than or equal to 19.8 percent organic matter from STATSGO

STATOM55_7 0 percent Percentage of soils with greater than 19.8 percent and less than or equal to 55.7 percent organic matter from STATSGO

LFREGNO 1544 undefined PKREGNO 1550 undefined DEVNLCD01 55.55 percent Percentage of land‐use categories 21‐24 from NLCD 2001

Flow Statistics Ungaged Site Report Date: Tues Oct 18, 2016 10:50:58 AM GMT‐4 Study Area: Virginia NAD 1983 Latitude: 38.6371 ( 38 38 14) NAD 1983 Longitude: ‐77.2307 (‐77 13 51) Drainage Area: 1 mi2

Peak Flows Region Basin Characteristics

100% Coastal Plain 2011 5144 (1 mi2)

Parameter Value Regression Equation Valid Range Min Max

Drainage Area (square miles) 1 0.06 7866

Low Flows Region Basin Characteristics

100% Coastal Plain 2011 5143 (1 mi2)

Parameter Value Regression Equation Valid Range Min Max

Drainage Area (square miles) 1 0.09 7393

Urban NLCD2001 Flows Region Basin Characteristics

100% Peak Urban01 2014 5090 (1 mi2)

Parameter Value Regression Equation Valid Range

Min Max Drainage Area (square miles) 1 0.07 2404 Percent developed from NLCD2001 (percent) 55.55 10 96

Urban Flows NLCD2006 Basin Characteristics

100% Peak Urban06 2014 5090 (1 mi2)

Parameter Value Regression Equation Valid Range

Min Max

Percent Developed from NLCD2006 (percent) 57.25 10 96

Urban Flows NLCD 2011 Basin Characteristics

100% Peak Urban11 2014 5090 (1 mi2)

Parameter Value Regression Equation Valid Range

Min Max

Percent Developed from NLCD2011 (percent) 47.3 10 96

Peak Flows Region Statistics

Statistic Value Unit Prediction Error (percent) Equivalent years of record 90‐Percent Prediction Interval

Min Max PK5 82.8 ft3/s 44

PK10 128 ft3/s 47 PK25 207 ft3/s 51 PK50 286 ft3/s 55 PK100 380 ft3/s 58 PK200 499 ft3/s 64 http://pubs.usgs.gov/sir/2011/5144/ (http://pubs.usgs.gov/sir/2011/5144/) Austin_ S.H._ Krstolic_ J.L._ and Wiegand_ Ute_ 2011_ Peak‐flow characteristics of Virginia streams: U.S. Geological Survey Scientific Investigations Report 2011–5144_ 106 p. + 3 tables and 2 appendixes on CD.

Low Flows Region Statistics

Statistic Value Unit Prediction Error (percent)

Equivalent years of record

90‐Percent Prediction Interval

Min Max M1D1 11Y 0.14 ft3/s 71 M1D1 25Y 0.0953 ft3/s 94 M1D1 43Y 0.0665 ft3/s 120 M1D1 67Y 0.0472 ft3/s 150 M1D2Y 0.033 ft3/s 190 M1D2 5Y 0.0203 ft3/s 400 M4D1 11Y 0.25 ft3/s 62 M4D1 25Y 0.18 ft3/s 77 M4D1 43Y 0.13 ft3/s 94 M4D1 67Y 0.0971 ft3/s 110 M4D2Y 0.0718 ft3/s 140 M4D2 5Y 0.0492 ft3/s 240 M7D1 11Y 0.29 ft3/s 56 M7D1 25Y 0.2 ft3/s 70 M7D1 43Y 0.15 ft3/s 85 M7D1 67Y 0.11 ft3/s 100 M7D2Y 0.0783 ft3/s 130 M7D2 5Y 0.0556 ft3/s 180 M30D1 11Y 0.46 ft3/s 35

M30D1 25Y 0.35 ft3/s 41

M30D1 43Y 0.26 ft3/s 53

M30D1 67Y 0.21 ft3/s 66

M30D2Y 0.16 ft3/s 84 M30D2 5Y 0.12 ft3/s 110 M30D3 33Y 0.0847 ft3/s 170 http://pubs.usgs.gov/sir/2011/5143/ (http://pubs.usgs.gov/sir/2011/5143/) Austin_ S.H._ Krstolic_ J.L._ and Wiegand_ Ute_ 2011_ Low‐flow characteristics of Virginia streams: U.S. Geological Survey Scientific Investigations Report 2011–5143_ 122 p. + 9 tables on CD.

Urban NLCD2001 Flows Region Statistics

90‐Percent Prediction Interval

Min Max PK1 005U 97.9 ft3/s 70 PK1 01U 104 ft3/s 68 http://pubs.usgs.gov/sir/2011/5144/ http://pubs.usgs.gov/sir/2011/5143/

PK1 05U 117 ft3/s 61 PK1 11U 138 ft3/s 59 PK1 25U 165 ft3/s 58 PK1 5U 198 ft3/s 57 PK2U 231 ft3/s 57 PK2 33U 254 ft3/s 57 PK5U 366 ft3/s 61 PK10U 492 ft3/s 64 PK25U 688 ft3/s 74 PK50U 896 ft3/s 85 PK100U 1150 ft3/s 98 PK200U 1450 ft3/s 100 PK500U 2100 ft3/s 130 http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014‐11‐21 ‐ Copy ‐ Copy.mdb# (http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014‐11‐ 21 ‐ Copy ‐ Copy.mdb#) Austin_ S.H._ 2014_ Methods and equations for estimating peak streamflow per square mile in Virginia’s urban basins: U.S. Geological Survey Scientific Investigations Report 2014–5090_ 25 p.

Urban Flows NLCD2006 Statistics

90‐Percent Prediction Interval

Min Max PK1 005U 103 ft3/s 70 PK1 01U 109 ft3/s 68 PK1 05U 122 ft3/s 61 PK1 11U 144 ft3/s 59 PK1 25U 171 ft3/s 58 PK1 5U 206 ft3/s 57 PK2U 240 ft3/s 57 PK2 33U 264 ft3/s 57 PK5U 379 ft3/s 61 PK10U 508 ft3/s 64 PK25U 707 ft3/s 74 PK50U 919 ft3/s 85 PK100U 1180 ft3/s 98 PK200U 1490 ft3/s 100 PK500U 2150 ft3/s 130 http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014‐11‐21 ‐ Copy ‐ Copy.mdb# (http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014‐11‐ 21 ‐ Copy ‐ Copy.mdb#) Austin_ S.H._ 2014_ Methods and equations for estimating peak streamflow per square mile in Virginia’s urban basins: U.S. Geological Survey Scientific

Urban Flows NLCD 2011 Statistics

90‐Percent Prediction Interval

Min Max PK1 005U 76.9 ft3/s 70 PK1 01U 82.4 ft3/s 68 PK1 05U 95.3 ft3/s 61 PK1 11U 114 ft3/s 59 PK1 25U 138 ft3/s 58 PK1 5U 163 ft3/s 57 PK2U 192 ft3/s 57 http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014-11-21 - Copy - Copy.mdb# http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014-11-21 - Copy - Copy.mdb#

PK2 33U 212 ft3/s 57 PK5U 309 ft3/s 61 PK10U 422 ft3/s 64 PK25U 605 ft3/s 74 PK50U 796 ft3/s 85 PK100U 1010 ft3/s 98 PK200U 1270 ft3/s 100 PK500U 1840 ft3/s 130 http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014‐11‐21 ‐ Copy ‐ Copy.mdb# (http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014‐11‐ 21 ‐ Copy ‐ Copy.mdb#) Austin_ S.H._ 2014_ Methods and equations for estimating peak streamflow per square mile in Virginia’s urban basins: U.S. Geological Survey Scientific

Accessibility FOIA Privacy Policies and Notices U.S. Department of the Interior | U.S. Geological Survey URL: http://streamstatsags.cr.usgs.gov/v3_beta/FTreport.htm Page Contact Information: StreamStats Help Streamstats Status News Page Last Modified: 11/24/2015 14:32:58 (Web1) http://pubs.usgs.gov/sir/2014/5090/#StreamStatsDB_2014-11-21 - Copy - Copy.mdb# http://www.usgs.gov/accessibility.html http://www.usgs.gov/foia/ http://www.usgs.gov/privacy.html http://www.usgs.gov/policies_notices.html http://usa.gov/ http://www.doi.gov/ http://www.usgs.gov/ mailto:support@streamstats.freshdesk.com javascript:openStatus('false');

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TIDAL INFORMATION

Station ID: 8635150 PUBLICATION DATE: 04/21/2003 Name: COLONIAL BEACH, POTOMAC RIVER * For NAVD 88, a positive value means the elevation is above the MLLW, a negative means the elevation is below the MLLW

VIRGINIA

NOAA Chart: 12286 Latitude: 38° 15.1' N USGS Quad: COLONIAL BEACH NORTH Longitude: 76° 57.6' W

Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

HIGHEST OBSERVED WATER LEVEL (09/06/1996) = 1.586 Datum MLLW MetNAVD 88 MNAVD 88 English

MEAN HIGHER HIGH WATER MHHW = 0.591 HOWL 1.586 1.285 4.216085

MEAN HIGH WATER MHW = 0.541 MHHW 0.591 0.29 0.95149

North American Vertical Datum NAVD88 = 0.301 MHW 0.541 0.24 0.78744

MEAN SEA LEVEL MSL = 0.293 MSL 0.293 ‐0.008 ‐0.02625

MEAN TIDE LEVEL MTL = 0.292 MTL 0.292 ‐0.009 ‐0.02953

MEAN LOW WATER MLW = 0.043 MLW 0.043 ‐0.258 ‐0.8465

MEAN LOWER LOW WATER MLLW = 0.000 MLLW 0 ‐0.301 ‐0.98758

LOWEST OBSERVED WATER LEVEL (04/04/1975) = ‐1.19 NAVD 88 0.301 0 0

LOWL ‐1.19 ‐1.491 ‐4.89197

Station ID: 8594900 PUBLICATION DATE: 09/05/2003 Name: WASHINGTON, POTOMAC RIVER

DISTRICT OF COLUMBIA

NOAA Chart: 12289 Latitude: 38° 52.4' N USGS Quad: WASHINGTON WEST Longitude: 77° 1.3' W

Elevations of tidal datums referred to Mean Lower Low Water (MLLW), in METERS:

"@" Subordinate Station (Indian Head, MD)

HIGHEST OBSERVED WATER LEVEL (10/17/1942) = 3.368 Datum MLLW MetNAVD 88 MNAVD 88 English MEAN HIGHER HIGH WATER MHHW = 0.965 HOWL 3.37 2.94 9.66 Mean Range 1.85 MEAN HIGH WATER MHW = 0.896 MHHW 0.97 0.54 1.77 Spring Range 2.50 MEAN SEA LEVEL MSL = 0.472 MHW 0.90 0.47 1.55 MTL 1.02 *assume MTL's are equivalent

MEAN TIDE LEVEL MTL = 0.471 MSL 0.47 0.05 0.15

North American Vertical Datum NAVD88 = 0.425 MTL 0.47 0.05 0.15 MHW 1.08 1.15 *predicted elevation on 10/6/16

MEAN LOW WATER MLW = 0.047 MLW 0.05 ‐0.38 ‐1.24 MLW ‐0.77

MEAN LOWER LOW WATER MLLW = 0.000 MLLW 0.00 ‐0.43 ‐1.39 MLLW ‐0.87

LOWEST OBSERVED WATER LEVEL (02/26/1967) = ‐1.539 NAVD 88 0.43 0.00 0.00 MHHW 1.63

LOWL ‐1.54 ‐1.96 ‐6.44

2016 Highest Predicted Tide 3.80 2.41 2.47 1.60 *referenced to datum of MLLW *apply listed height offset of 0.65

NOAA/NOS/CO‐OPS

Disclaimer: These data are based upon the latest information available as of the date of your request, and may differ from the published tide tables.

Product Type: Annual Tide Prediction StationName: Indian Head, Md.

State: MD Stationid: 8579381 ReferencedToStationName: Washington ReferenceToStationId: 8594900 Mean Range 1.85

HeightOffsetLow: *0.73 HeightOffsetHigh: * 0.65 Spring Range 2.50

TimeOffsetLow: ‐93 TimeOffsetHigh: ‐14 Prediction Type: Subordinate MHW 1.94 From: 20151231 12:00AM ‐ 20161231 11:59PM Units: feet(ft) also in centimeters(cm) MLW 0.09 Time Zone: LST/LDT Datum: MLLW MTL 1.02 Interval Type: High/Low Tide Predictions

The NOAA Tide Predictions application provides predictions in both graphical and tabular formats, with many user selected options, for over 3000 stations broken down by key areas in each state.

Users can also access stations via the Google map interface. Additional information can be found in the help page.

Station Types: The NOAA Tide Predictions application provides predictions from 2 distinct categories of stations at over 3000 locations:

Harmonic - The predicted height values for Harmonic stations are conducted by combining the harmonic constituents into a single tide curve.

Subordinate - The high and low height values for Subordinate stations are obtained by means and differences, and ratios applied to the full harmonic constant predictions at a specific Harmonic station (a Reference station).

Disclaimer: The official Tide prediction tables are published annually on October 1, for the following calendar year. Tide predictions generated prior to the publishing date of the official tables are subject to change. The predictions from the web based NOAA Tidal Predictions are based upon the latest information available as of the date of your request. Tide predictions generated may differ from the official published predictions if information for the station requested has been updated since the publishing date of the official published tables.

NOAA Tide Predictions

WASHINGTON, Washington Channel, D.C.,District of Columbia,2016

Generated On: Thu Nov 17 18:48:51 UTC 2016 Page 1 of 5

January February March Time Height Time Height Time Height Time Height Time Height Time Height

F h m ft cm

12:43 AM 2.4 73

07:33 AM -0.1 -3

01:12 PM 2.4 73

08:02 PM 0.1 3

Sa h m ft cm

12:20 AM 2.7 82

07:30 AM -0.4 -12

12:49 PM 2.8 85

08:12 PM -0.3 -9

M h m ft cm

01:40 AM 2.3 70

07:53 AM 0.0 0

01:51 PM 2.5 76

08:57 PM 0.2 6

Tu h m ft cm

02:12 AM 2.6 79

09:03 AM -0.1 -3

02:32 PM 2.9 88

10:00 PM -0.1 -3

Tu h m ft cm

12:51 AM 2.5 76

07:10 AM 0.2 6

12:52 PM 2.8 85

08:06 PM 0.3 9

W h m ft cm

02:55 AM 2.8 85

09:45 AM 0.1 3

03:13 PM 3.0 91

10:38 PM 0.1 3

Sa

01:36 AM 2.3 70

08:13 AM 0.0 0

02:03 PM 2.4 73

08:54 PM 0.1 3

Su

01:22 AM 2.6 79

08:24 AM -0.3 -9

01:49 PM 2.8 85

09:16 PM -0.2 -6

Tu

02:34 AM 2.2 67

08:43 AM 0.0 0

02:43 PM 2.5 76

09:57 PM 0.2 6

W

03:15 AM 2.6 79

10:06 AM -0.1 -3

03:36 PM 2.9 88

11:01 PM -0.1 -3

W

01:43 AM 2.5 76

08:00 AM 0.2 6

01:44 PM 2.7 82

09:05 PM 0.4 12

Th

03:58 AM 2.8 85

10:48 AM 0.2 6

04:19 PM 2.9 88

11:37 PM 0.1 3

Su

02:31 AM 2.2 67

08:56 AM 0.0 0

02:55 PM 2.4 73

09:50 PM 0.1 3

M

02:27 AM 2.5 76

09:22 AM -0.3 -9

02:52 PM 2.8 85

10:19 PM -0.3 -9

W

03:30 AM 2.2 67

09:39 AM 0.0 0

03:38 PM 2.5 76

10:58 PM 0.2 6

Th

04:17 AM 2.6 79

11:08 AM -0.1 -3

04:38 PM 2.8 85

11:58 PM -0.2 -6

Th

02:40 AM 2.4 73

08:58 AM 0.2 6

02:43 PM 2.7 82

10:11 PM 0.3 9

F

04:59 AM 2.8 85

11:49 AM 0.1 3

05:21 PM 2.9 88

M

03:25 AM 2.2 67

09:43 AM 0.0 0

03:46 PM 2.4 73

10:47 PM 0.1 3

Tu

03:31 AM 2.5 76

10:24 AM -0.3 -9

03:54 PM 2.8 85

11:21 PM -0.3 -9

Th

04:24 AM 2.2 67

10:43 AM 0.0 0

04:32 PM 2.6 79

11:56 PM 0.1 3

F

05:14 AM 2.6 79

12:07 PM -0.1 -3

05:36 PM 2.9 88

F

03:39 AM 2.5 76

10:04 AM 0.3 9

03:47 PM 2.8 85

11:15 PM 0.3 9

Sa

12:33 AM 0.1 3

05:55 AM 2.9 88

12:48 PM 0.1 3

06:19 PM 2.9 88

Tu

04:18 AM 2.2 67

10:35 AM 0.0 0

04:34 PM 2.5 76

11:42 PM 0.1 3

W

04:33 AM 2.5 76

11:25 AM -0.3 -9

04:54 PM 2.9 88

F

05:16 AM 2.3 70

11:47 AM 0.0 0

05:25 PM 2.6 79

Sa

12:52 AM -0.2 -6

06:08 AM 2.7 82

01:02 PM -0.2 -6

06:30 PM 2.9 88

Sa

04:35 AM 2.6 79

11:15 AM 0.2 6

04:48 PM 2.8 85

Su

01:25 AM 0.1 3

06:47 AM 3.0 91

01:42 PM 0.1 3

07:11 PM 3.0 91

W

05:09 AM 2.2 67

11:29 AM -0.1 -3

05:20 PM 2.5 76

Th

12:19 AM -0.4 -12

05:30 AM 2.5 76

12:23 PM -0.3 -9

05:51 PM 2.9 88

Sa

12:50 AM 0.0 0

06:05 AM 2.4 73

12:47 PM -0.1 -3

06:15 PM 2.7 82

Su

01:42 AM -0.2 -6

06:57 AM 2.8 85

01:54 PM -0.2 -6

07:19 PM 2.9 88

Su

12:13 AM 0.2 6

05:29 AM 2.7 82

12:22 PM 0.1 3

05:46 PM 2.9 88

M

02:13 AM 0.1 3

07:36 AM 3.0 91

02:33 PM 0.0 0

07:59 PM 3.0 91

Th

12:34 AM 0.0 0

05:56 AM 2.3 70

12:23 PM -0.1 -3

06:04 PM 2.6 79

F

01:14 AM -0.4 -12

06:25 AM 2.6 79

01:19 PM -0.4 -12

06:44 PM 2.9 88

Su

01:41 AM -0.1 -3

06:51 AM 2.5 76

01:43 PM -0.2 -6

07:04 PM 2.8 85

M

02:28 AM -0.2 -6

07:44 AM 2.8 85

02:41 PM -0.2 -6

08:05 PM 2.9 88

M

01:07 AM 0.1 3

06:19 AM 2.9 88

01:22 PM 0.0 0

06:39 PM 3.0 91

Tu

02:58 AM 0.1 3

08:20 AM 3.1 94

03:20 PM 0.0 0

08:44 PM 3.0 91

F

01:24 AM -0.1 -3

06:40 AM 2.3 70

01:15 PM -0.2 -6

06:46 PM 2.7 82

Sa

02:06 AM -0.4 -12

07:16 AM 2.6 79

02:11 PM -0.4 -12

07:35 PM 2.9 88

M

02:29 AM -0.2 -6

07:35 AM 2.6 79

02:36 PM -0.3 -9

07:52 PM 2.9 88

Tu

03:10 AM -0.2 -6

08:27 AM 2.8 85

03:26 PM -0.2 -6

08:49 PM 2.9 88

Tu

01:57 AM -0.1 -3

07:07 AM 3.0 91

02:18 PM -0.1 -3

07:31 PM 3.1 94

W

03:38 AM 0.1 3

09:02 AM 3.1 94

04:03 PM 0.0 0

09:26 PM 3.0 91

Sa

02:11 AM -0.2 -6

07:22 AM 2.4 73

02:05 PM -0.2 -6

07:28 PM 2.8 85

Su

02:54 AM -0.4 -12

08:04 AM 2.6 79

03:00 PM -0.4 -12

08:23 PM 2.9 88

Tu

03:15 AM -0.3 -9

08:20 AM 2.8 85

03:28 PM -0.3 -9

08:39 PM 3.0 91

W

03:49 AM -0.1 -3

09:08 AM 2.9 88

04:08 PM -0.1 -3

09:30 PM 2.8 85

W

02:45 AM -0.2 -6

07:55 AM 3.2 98

03:11 PM -0.2 -6

08:21 PM 3.2 98

Th

04:15 AM 0.2 6

09:39 AM 3.1 94

04:44 PM 0.1 3

10:05 PM 2.9 88

Su

02:57 AM -0.3 -9

08:03 AM 2.4 73

02:53 PM -0.3 -9

08:11 PM 2.8 85

M

03:39 AM -0.4 -12

08:50 AM 2.6 79

03:47 PM -0.4 -12

09:09 PM 2.8 85

W

04:00 AM -0.4 -12

09:05 AM 2.9 88

04:19 PM -0.4 -12

09:28 PM 3.0 91

Th

04:24 AM 0.0 0

09:46 AM 2.9 88

04:47 PM 0.0 0

10:09 PM 2.8 85

Th

03:32 AM -0.2 -6

08:42 AM 3.3 101

04:04 PM -0.3 -9

09:11 PM 3.2 98

F

04:48 AM 0.2 6

10:14 AM 3.1 94

05:22 PM 0.2 6

10:42 PM 2.9 88

M

03:41 AM -0.3 -9

08:44 AM 2.5 76

03:42 PM -0.3 -9

08:55 PM 2.9 88

Tu

04:20 AM -0.3 -9

09:34 AM 2.6 79

04:31 PM -0.3 -9

09:53 PM 2.7 82

Th

04:44 AM -0.4 -12

09:51 AM 3.0 91

05:10 PM -0.4 -12

10:18 PM 3.0 91

F

04:55 AM 0.0 0

10:22 AM 2.8 85

05:24 PM 0.0 0

10:48 PM 2.7 82

F

04:19 AM -0.2 -6

09:30 AM 3.4 104

04:56 PM -0.3 -9

10:03 PM 3.1 94

Sa

05:17 AM 0.2 6

10:46 AM 3.1 94

05:58 PM 0.2 6

11:18 PM 2.8 85

Tu

04:25 AM -0.4 -12

09:26 AM 2.6 79

04:31 PM -0.3 -9

09:41 PM 2.9 88

W

04:59 AM -0.2 -6

10:17 AM 2.6 79

05:13 PM -0.2 -6

10:36 PM 2.6 79

F

05:30 AM -0.4 -12

10:40 AM 3.0 91

06:04 PM -0.4 -12

11:11 PM 2.9 88

Sa

05:23 AM 0.1 3

10:56 AM 2.8 85

06:00 PM 0.1 3

11:26 PM 2.6 79

Sa

05:06 AM -0.2 -6

10:19 AM 3.4 104

05:49 PM -0.3 -9

10:56 PM 3.0 91

Su

05:45 AM 0.3 9

11:15 AM 3.1 94

06:32 PM 0.3 9

11:53 PM 2.8 85

W

05:09 AM -0.4 -12

10:11 AM 2.7 82

05:22 PM -0.3 -9

10:30 PM 2.9 88

Th

05:35 AM -0.2 -6

10:58 AM 2.6 79

05:54 PM -0.1 -3

11:19 PM 2.5 76

Sa

06:18 AM -0.4 -12

11:32 AM 3.0 91

06:59 PM -0.3 -9

Su

05:51 AM 0.1 3

11:30 AM 2.8 85

06:36 PM 0.2 6

Su

06:56 AM -0.2 -6

12:11 PM 3.3 101

07:43 PM -0.2 -6

M

06:16 AM 0.3 9

11:48 AM 3.1 94

07:07 PM 0.3 9

Th

05:53 AM -0.4 -12

11:00 AM 2.7 82

06:15 PM -0.3 -9

11:23 PM 2.8 85

F

06:07 AM -0.1 -3

11:39 AM 2.6 79

06:34 PM 0.0 0

Su

12:07 AM 2.8 85

07:08 AM -0.3 -9

12:28 PM 3.0 91

07:58 PM -0.2 -6

M

12:07 AM 2.6 79

06:27 AM 0.1 3

12:07 PM 2.8 85

07:17 PM 0.3 9

M

12:53 AM 3.0 91

07:48 AM -0.1 -3

01:08 PM 3.2 98

08:40 PM -0.1 -3

Tu

12:30 AM 2.8 85

06:54 AM 0.3 9

12:26 PM 3.1 94

07:45 PM 0.4 12

F

06:40 AM -0.4 -12

11:52 AM 2.8 85

07:12 PM -0.3 -9

Sa

12:03 AM 2.4 73

06:38 AM -0.1 -3

12:20 PM 2.5 76

07:16 PM 0.1 3

M

01:08 AM 2.7 82

08:03 AM -0.2 -6

01:29 PM 2.9 88

08:58 PM -0.2 -6

Tu

01:53 AM 2.9 88

08:45 AM 0.0 0

02:08 PM 3.1 94

09:39 PM 0.0 0

W

01:12 AM 2.7 82

07:39 AM 0.4 12

01:11 PM 3.1 94

08:31 PM 0.4 12

Su

12:50 AM 2.4 73

07:12 AM 0.0 0

01:04 PM 2.5 76

08:03 PM 0.1 3

Th

02:01 AM 2.7 82

08:30 AM 0.4 12

02:04 PM 3.0 91

09:26 PM 0.5 15

StationId:8594900 Source:NOAA/NOS/CO-OPS Station Type:Harmonic Time Zone:LST/LDT Datum:mean lower low water (MLLW) which is the chart datum of soundings

NOAA Tide Predictions

WASHINGTON, Washington Channel, D.C.,District of Columbia,2016

Times and Heights of High and Low Waters

Disclaimer: These data are based upon the latest information available as of the date of your request, and may differ from the published tide tables.

Generated On: Thu Nov 17 18:48:51 UTC 2016 Page 2 of 5

April May June Time Height Time Height Time Height Time Height Time Height Time Height

F h m ft cm

02:57 AM 2.7 82

09:29 AM 0.4 12

03:04 PM 3.0 91

10:29 PM 0.5 15

Sa h m ft cm

04:36 AM 3.0 91

11:27 AM 0.4 12

04:59 PM 3.0 91

Su h m ft cm

03:26 AM 3.0 91

10:19 AM 0.5 15

03:43 PM 3.1 94

10:56 PM 0.4 12

M h m ft cm

05:02 AM 3.1 94

11:55 AM 0.5 15

05:25 PM 2.9 88

W h m ft cm

05:00 AM 3.4 104

12:23 PM 0.3 9

05:32 PM 3.1 94

Th h m ft cm

12:11 AM 0.4 12

06:04 AM 3.2 98

01:07 PM 0.4 12

06:32 PM 2.8 85

Sa

03:58 AM 2.8 85

10:37 AM 0.4 12

04:10 PM 3.0 91

11:33 PM 0.4 12

Su

12:01 AM 0.3 9

05:32 AM 3.1 94

12:24 PM 0.3 9

05:55 PM 3.0 91

M

04:27 AM 3.2 98

11:32 AM 0.4 12

04:50 PM 3.1 94

11:57 PM 0.3 9

Tu

12:12 AM 0.4 12

05:53 AM 3.2 98

12:49 PM 0.4 12

06:17 PM 2.9 88

Th

12:25 AM 0.2 6

05:57 AM 3.6 110

01:25 PM 0.1 3

06:32 PM 3.1 94

F

12:57 AM 0.4 12

06:48 AM 3.2 98

01:56 PM 0.4 12

07:19 PM 2.8 85

Su

04:58 AM 2.9 88

11:50 AM 0.4 12

05:16 PM 3.0 91

M

12:52 AM 0.3 9

06:23 AM 3.1 94

01:18 PM 0.3 9

06:47 PM 3.0 91

Tu

05:26 AM 3.3 101

12:40 PM 0.3 9

05:53 PM 3.2 98

W

12:58 AM 0.4 12

06:39 AM 3.2 98

01:40 PM 0.4 12

07:05 PM 2.9 88

F

01:24 AM 0.1 3

06:52 AM 3.7 113

02:23 PM 0.0 0

07:29 PM 3.1 94

Sa

01:43 AM 0.4 12

07:29 AM 3.2 98

02:41 PM 0.3 9

08:02 PM 2.8 85

M

12:34 AM 0.3 9

05:55 AM 3.1 94

12:59 PM 0.3 9

06:18 PM 3.1 94

Tu

01:39 AM 0.3 9

07:10 AM 3.2 98

02:08 PM 0.2 6

07:34 PM 3.0 91

W

12:55 AM 0.2 6

06:21 AM 3.5 107

01:42 PM 0.2 6

06:52 PM 3.2 98

Th

01:41 AM 0.4 12

07:22 AM 3.3 101

02:27 PM 0.3 9

07:50 PM 2.9 88

Sa

02:21 AM 0.1 3

07:45 AM 3.8 116

03:18 PM -0.1 -3

08:23 PM 3.2 98

Su

02:27 AM 0.4 12

08:06 AM 3.2 98

03:25 PM 0.3 9

08:43 PM 2.8 85

Tu

01:30 AM 0.2 6

06:49 AM 3.2 98

02:01 PM 0.1 3

07:15 PM 3.2 98

W

02:22 AM 0.3 9

07:53 AM 3.3 101

02:55 PM 0.2 6

08:18 PM 3.0 91

Th

01:51 AM 0.2 6

07:14 AM 3.7 113

02:41 PM 0.0 0

07:48 PM 3.2 98

F

02:23 AM 0.4 12

08:02 AM 3.3 101

03:11 PM 0.3 9

08:32 PM 2.9 88

Su

03:16 AM 0.1 3

08:37 AM 3.8 116

04:11 PM -0.1 -3

09:16 PM 3.2 98

M

03:10 AM 0.4 12

08:42 AM 3.3 101

04:07 PM 0.2 6

09:21 PM 2.8 85

W

02:23 AM 0.1 3

07:40 AM 3.4 104

02:59 PM 0.0 0

08:09 PM 3.2 98

Th

03:02 AM 0.3 9

08:33 AM 3.3 101

03:38 PM 0.2 6

09:00 PM 3.0 91

F

02:45 AM 0.1 3

08:05 AM 3.8 116

03:36 PM -0.1 -3

08:41 PM 3.3 101

Sa

03:02 AM 0.4 12

08:38 AM 3.3 101

03:53 PM 0.3 9

09:12 PM 2.9 88

M

04:10 AM 0.1 3

09:28 AM 3.7 113

05:01 PM -0.1 -3

10:08 PM 3.2 98

Tu

03:53 AM 0.4 12

09:16 AM 3.3 101

04:48 PM 0.2 6

09:57 PM 2.9 88

Th

03:14 AM 0.0 0

08:29 AM 3.6 110

03:54 PM -0.1 -3

09:01 PM 3.3 101

F

03:38 AM 0.4 12

09:09 AM 3.3 101

04:19 PM 0.2 6

09:39 PM 3.0 91

Sa

03:37 AM 0.1 3

08:56 AM 3.8 116

04:29 PM -0.1 -3

09:34 PM 3.3 101

Su

03:39 AM 0.4 12

09:11 AM 3.3 101

04:33 PM 0.3 9

09:49 PM 2.9 88

Tu

05:03 AM 0.1 3

10:19 AM 3.6 110

05:51 PM -0.1 -3

11:00 PM 3.1 94

W

04:36 AM 0.4 12

09:52 AM 3.3 101

05:27 PM 0.2 6

10:33 PM 2.9 88

F

04:03 AM 0.0 0

09:18 AM 3.7 113

04:47 PM -0.2 -6

09:53 PM 3.3 101

Sa

04:12 AM 0.4 12

09:42 AM 3.3 101

04:58 PM 0.3 9

10:16 PM 2.9 88

Su

04:30 AM 0.1 3

09:46 AM 3.8 116

05:21 PM -0.1 -3

10:27 PM 3.2 98

M

04:16 AM 0.4 12

09:42 AM 3.3 101

05:12 PM 0.3 9

10:24 PM 2.9 88

W

05:55 AM 0.2 6

11:11 AM 3.5 107

06:40 PM 0.0 0

11:53 PM 3.1 94

Th

05:20 AM 0.4 12

10:32 AM 3.3 101

06:07 PM 0.2 6

11:12 PM 3.0 91

Sa

04:53 AM 0.0 0

10:07 AM 3.7 113

05:39 PM -0.2 -6

10:45 PM 3.2 98

Su

04:44 AM 0.4 12

10:12 AM 3.3 101

05:34 PM 0.3 9

10:50 PM 2.9 88

M

05:22 AM 0.1 3

10:37 AM 3.7 113

06:13 PM -0.1 -3

11:21 PM 3.2 98

Tu

04:54 AM 0.5 15

10:14 AM 3.3 101

05:49 PM 0.3 9

10:58 PM 2.9 88

Th

06:47 AM 0.3 9

12:04 PM 3.3 101

07:28 PM 0.1 3

F

06:06 AM 0.4 12

11:16 AM 3.3 101

06:47 PM 0.2 6

11:55 PM 3.1 94

Su

05:43 AM 0.0 0

10:58 AM 3.6 110

06:32 PM -0.1 -3

11:39 PM 3.2 98

M

05:16 AM 0.4 12

10:41 AM 3.3 101

06:10 PM 0.4 12

11:24 PM 2.9 88

Tu

06:15 AM 0.2 6

11:30 AM 3.6 110

07:04 PM 0.0 0

W

05:33 AM 0.5 15

10:51 AM 3.3 101

06:27 PM 0.3 9

11:35 PM 2.9 88

F

12:47 AM 3.1 94

07:40 AM 0.4 12

01:00 PM 3.1 94

08:15 PM 0.2 6

Sa

06:56 AM 0.4 12

12:04 PM 3.3 101

07:30 PM 0.2 6

M

06:35 AM 0.1 3

11:51 AM 3.5 107

07:25 PM -0.1 -3

Tu

05:51 AM 0.5 15

11:15 AM 3.3 101

06:46 PM 0.4 12

W

12:16 AM 3.1 94

07:09 AM 0.3 9

12:26 PM 3.4 104

07:56 PM 0.1 3

Th

06:16 AM 0.5 15

11:33 AM 3.3 101

07:07 PM 0.3 9

Sa

01:42 AM 3.0 91

08:34 AM 0.5 15

01:57 PM 3.0 91

09:03 PM 0.3 9

Su

12:44 AM 3.1 94

07:51 AM 0.4 12

12:58 PM 3.2 98

08:15 PM 0.2 6

Tu

12:36 AM 3.1 94

07:29 AM 0.2 6

12:47 PM 3.4 104

08:20 PM 0.1 3

W

12:00 AM 2.9 88

06:31 AM 0.5 15

11:56 AM 3.3 101

07:24 PM 0.4 12

Th

01:13 AM 3.1 94

08:05 AM 0.4 12

01:26 PM 3.2 98

08:48 PM 0.2 6

F

12:17 AM 3.0 91

07:04 AM 0.5 15

12:21 PM 3.3 101

07:50 PM 0.3 9

Su

02:37 AM 3.0 91

09:29 AM 0.5 15

02:56 PM 2.9 88

09:50 PM 0.4 12

M

01:37 AM 3.2 98

08:51 AM 0.4 12

01:58 PM 3.1 94

09:06 PM 0.2 6

W

01:35 AM 3.0 91

08:26 AM 0.3 9

01:48 PM 3.2 98

09:15 PM 0.2 6

Th

12:42 AM 2.9 88

07:18 AM 0.5 15

12:42 PM 3.2 98

08:08 PM 0.4 12

F

02:12 AM 3.0 91

09:02 AM 0.4 12

02:28 PM 3.1 94

09:40 PM 0.3 9

Sa

01:06 AM 3.0 91

07:58 AM 0.5 15

01:15 PM 3.2 98

08:37 PM 0.3 9

M

03:32 AM 3.0 91

10:25 AM 0.5 15

03:54 PM 2.8 85

10:37 PM 0.4 12

Tu

02:36 AM 3.3 101

09:57 AM 0.4 12

03:03 PM 3.0 91

10:01 PM 0.2 6

Th

02:36 AM 3.0 91

09:26 AM 0.3 9

02:53 PM 3.1 94

10:12 PM 0.2 6

F

01:30 AM 2.9 88

08:10 AM 0.5 15

01:36 PM 3.2 98

08:59 PM 0.4 12

Sa

03:11 AM 3.0 91

10:01 AM 0.5 15

03:30 PM 3.0 91

10:32 PM 0.4 12

Su

02:00 AM 3.1 94

08:59 AM 0.5 15

02:15 PM 3.1 94

09:29 PM 0.3 9

Tu

04:26 AM 3.1 94

11:21 AM 0.5 15

04:50 PM 2.8 85

11:24 PM 0.4 12

W

03:37 AM 3.4 104

11:03 AM 0.3 9

04:10 PM 3.0 91

11:01 PM 0.2 6

F

03:38 AM 3.0 91

10:27 AM 0.4 12

03:57 PM 3.0 91

11:08 PM 0.3 9

Sa

02:26 AM 3.0 91

09:10 AM 0.5 15

02:36 PM 3.1 94

09:56 PM 0.4 12

Su

04:08 AM 3.1 94

10:59 AM 0.5 15

04:30 PM 2.9 88

11:23 PM 0.4 12

M

02:59 AM 3.2 98

10:07 AM 0.5 15

03:21 PM 3.1 94

10:26 PM 0.3 9

W

05:16 AM 3.1 94

12:15 PM 0.5 15

05:42 PM 2.7 82

Th

04:38 AM 3.4 104

12:08 PM 0.2 6

05:14 PM 3.0 91

Tu

04:00 AM 3.3 101

11:17 AM 0.4 12

04:28 PM 3.1 94

11:25 PM 0.2 6

StationId:8594900 Source:NOAA/NOS/CO-OPS Station Type:Harmonic Time Zone:LST/LDT Datum:mean lower low water (MLLW) which is the chart datum of soundings

NOAA Tide Predictions

WASHINGTON, Washington Channel, D.C.,District of Columbia,2016

Times and Heights of High and Low Waters

Disclaimer: These data are based upon the latest information available as of the date of your request, and may differ from the published tide tables.

Generated On: Thu Nov 17 18:48:51 UTC 2016 Page 3 of 5

July August September Time Height Time Height Time Height Time Height Time Height Time Height

F h m ft cm

12:03 AM 0.2 6

05:37 AM 3.5 107

01:09 PM 0.1 3

06:15 PM 3.0 91

Sa h m ft cm

12:11 AM 0.5 15

06:09 AM 3.1 94

01:21 PM 0.5 15

06:45 PM 2.7 82

M h m ft cm

01:50 AM 0.1 3

07:16 AM 3.5 107

02:40 PM 0.0 0

07:51 PM 3.1 94

Tu h m ft cm

01:26 AM 0.4 12

07:03 AM 3.2 98

02:22 PM 0.3 9

07:39 PM 2.9 88

Th h m ft cm

03:18 AM 0.1 3

08:41 AM 3.4 104

03:49 PM 0.1 3

09:06 PM 3.3 101

F h m ft cm

02:51 AM 0.2 6

08:07 AM 3.4 104

03:18 PM 0.1 3

08:32 PM 3.4 104

Sa

01:05 AM 0.1 3

06:34 AM 3.6 110

02:06 PM 0.0 0

07:12 PM 3.0 91

Su

01:04 AM 0.4 12

06:53 AM 3.1 94

02:09 PM 0.4 12

07:30 PM 2.7 82

Tu

02:45 AM 0.1 3

08:08 AM 3.5 107

03:30 PM 0.0 0

08:41 PM 3.2 98

W

02:20 AM 0.4 12

07:47 AM 3.3 101

03:07 PM 0.2 6

08:20 PM 3.0 91

F

04:05 AM 0.2 6

09:25 AM 3.4 104

04:29 PM 0.1 3

09:48 PM 3.3 101

Sa

03:43 AM 0.1 3

08:54 AM 3.4 104

04:03 PM 0.0 0

09:16 PM 3.5 107

Su

02:03 AM 0.1 3

07:29 AM 3.6 110

03:00 PM -0.1 -3

08:06 PM 3.1 94

M

01:55 AM 0.4 12

07:35 AM 3.2 98

02:55 PM 0.3 9

08:12 PM 2.8 85

W

03:36 AM 0.1 3

08:57 AM 3.5 107

04:16 PM 0.0 0

09:28 PM 3.2 98

Th

03:12 AM 0.3 9

08:31 AM 3.4 104

03:51 PM 0.1 3

09:01 PM 3.2 98

Sa

04:49 AM 0.2 6

10:07 AM 3.3 101

05:06 PM 0.2 6

10:28 PM 3.3 101

Su

04:34 AM 0.1 3

09:41 AM 3.4 104

04:47 PM 0.0 0

10:01 PM 3.6 110

M

02:59 AM 0.1 3

08:21 AM 3.6 110

03:51 PM -0.1 -3

08:58 PM 3.1 94

Tu

02:45 AM 0.4 12

08:14 AM 3.3 101

03:39 PM 0.2 6

08:51 PM 2.9 88

Th

04:25 AM 0.1 3

09:44 AM 3.4 104

04:59 PM 0.0 0

10:14 PM 3.2 98

F

04:01 AM 0.2 6

09:14 AM 3.4 104

04:33 PM 0.1 3

09:42 PM 3.3 101

Su

05:31 AM 0.3 9

10:48 AM 3.2 98

05:39 PM 0.3 9

11:06 PM 3.3 101

M

05:26 AM 0.1 3

10:29 AM 3.4 104

05:33 PM 0.0 0

10:48 PM 3.6 110

Tu

03:53 AM 0.1 3

09:12 AM 3.6 110

04:40 PM -0.1 -3

09:49 PM 3.1 94

W

03:32 AM 0.3 9

08:53 AM 3.3 101

04:21 PM 0.1 3

09:29 PM 3.0 91

F

05:12 AM 0.2 6

10:30 AM 3.3 101

05:40 PM 0.1 3

10:58 PM 3.2 98

Sa

04:51 AM 0.2 6

09:59 AM 3.4 104

05:15 PM 0.0 0

10:25 PM 3.4 104

M

06:11 AM 0.4 12

11:27 AM 3.1 94

06:08 PM 0.4 12

11:42 PM 3.2 98

Tu

06:19 AM 0.1 3

11:20 AM 3.3 101

06:22 PM 0.1 3

11:38 PM 3.6 110

W

04:44 AM 0.1 3

10:02 AM 3.5 107

05:27 PM -0.1 -3

10:38 PM 3.1 94

Th

04:19 AM 0.3 9

09:33 AM 3.4 104

05:02 PM 0.1 3

10:08 PM 3.0 91

Sa

05:57 AM 0.3 9

11:14 AM 3.2 98

06:18 PM 0.2 6

11:41 PM 3.2 98

Su

05:41 AM 0.2 6

10:45 AM 3.4 104

05:58 PM 0.0 0

11:10 PM 3.5 107

Tu

06:50 AM 0.6 18

12:07 PM 2.9 88

06:35 PM 0.4 12

W

07:14 AM 0.2 6

12:14 PM 3.2 98

07:14 PM 0.1 3

Th

05:34 AM 0.2 6

10:51 AM 3.4 104

06:12 PM 0.0 0

11:27 PM 3.1 94

F

05:06 AM 0.3 9

10:15 AM 3.4 104

05:42 PM 0.1 3

10:49 PM 3.1 94

Su

06:41 AM 0.4 12

11:59 AM 3.1 94

06:53 PM 0.3 9

M

06:34 AM 0.2 6

11:35 AM 3.3 101

06:44 PM 0.1 3

11:59 PM 3.5 107

W

12:18 AM 3.1 94

07:30 AM 0.6 18

12:49 PM 2.8 85

07:09 PM 0.5 15

Th

12:33 AM 3.5 107

08:12 AM 0.2 6

01:14 PM 3.0 91

08:12 PM 0.2 6

F

06:23 AM 0.3 9

11:40 AM 3.2 98

06:55 PM 0.1 3

Sa

05:55 AM 0.3 9

11:01 AM 3.3 101

06:24 PM 0.1 3

11:33 PM 3.2 98

M

12:24 AM 3.1 94

07:26 AM 0.5 15

12:44 PM 2.9 88

07:26 PM 0.4 12

Tu

07:29 AM 0.3 9

12:29 PM 3.2 98

07:33 PM 0.1 3

Th

12:57 AM 3.1 94

08:13 AM 0.7 21

01:36 PM 2.7 82

07:51 PM 0.5 15

F

01:34 AM 3.4 104

09:12 AM 0.3 9

02:19 PM 2.9 88

09:14 PM 0.3 9

Sa

12:15 AM 3.1 94

07:12 AM 0.4 12

12:30 PM 3.1 94

07:37 PM 0.2 6

Su

06:46 AM 0.3 9

11:49 AM 3.3 101

07:07 PM 0.1 3

Tu

01:08 AM 3.1 94

08:11 AM 0.6 18

01:33 PM 2.8 85

07:59 PM 0.4 12

W

12:53 AM 3.5 107

08:28 AM 0.3 9

01:28 PM 3.1 94

08:27 PM 0.2 6

F

01:42 AM 3.0 91

09:04 AM 0.8 24

02:30 PM 2.7 82

08:41 PM 0.6 18

Sa

02:41 AM 3.3 101

10:12 AM 0.3 9

03:26 PM 2.9 88

10:18 PM 0.3 9

Su

01:05 AM 3.0 91

08:01 AM 0.5 15

01:22 PM 2.9 88

08:17 PM 0.3 9

M

12:21 AM 3.3 101

07:41 AM 0.3 9

12:43 PM 3.2 98

07:54 PM 0.1 3

W

01:55 AM 3.0 91

09:01 AM 0.7…