# Presentation: 521937

## IMAGING NOS SUPERSEDED PUBLISHED BENCH MARK SHEETS
New FY09 Task

**New FY09 Task**

**Stephen D. Lyles**

**NOAA’s NATIONAL OCEAN SERVICE**
- Center for Operational Oceanographic Products and Services
- (CO-OPS)

## Database Utilization

- Climate Research Change
- Determination of landward edge of a marine boundary
- GIS based systems to monitor boundary changes, upheaval and subsidence rates for land movement

## NATIONAL TIDAL DATUM EPOCH

**Averages out long term seasonal meteorological, hydrologic, ****	****and ****	****oceanographic fluctuations.**
** ****Provides a nationally consistent tidal datum network (bench ****	****marks) by accounting for seasonal and apparent environmental ****	****trends in sea level that affects the accuracy of tidal datums.**
**The NWLON provides the data required to maintain the epoch                                                                                                                                                                                        ****	****and make primary and secondary determinations of tidal ****	****datums.**

**NATIONAL TIDAL DATUM EPOCH**

**Notes:**
To begin to understand datums, you need to understand what an epoch is and why we have them.  
Epoch is how long it takes for the Sun, Moon, & Earth complete epoch tidal cycle
This takes 18.6 yrs, so we use 19 yrs (because statistically the 0.4 is not significant out of the 19 yr avg.)
What this means is that the NOS has a standard for creating 19 year means.

## IDEALIZED CHANGE OF TIDAL EPOCH

**1983-01 EPOCH**

**Notes:**
We need a change in Epoch to keep water levels and in turn depths up to date.... If we had continued on the 41-59 epoch we would be nearly half a foot off or more in certain areas such as Louisiana, Texas, and Alaska

## MHHW

**MHHW**

**Notes:**
Highest and Lowest Observed are not a tidal datum or a computation.
The acronyms can be found in our reference Glossary

Standard Method (MTL, MSL, Mn, DHQ & DLG are known):
MLW= MTL-(0.5*Mn)
MHW= MLW+Mn
MLLW= MLW-DLQ
MHHW= MHW-DHQ
DTL= 0.5*(MHHW+MLLW)
GT= MHHW-MLLW

MRR Method (MTL, DTL, MSL, Mn & GT are known):
MLW= MTL-(0.5*Mn)
MHW= MLW+Mn
MLLW= MLW-0.5*GT
MHHW= MHW+GT
DHQ= MHHW-MHW
DLQ= MLW-MLLW

GT is known as the spring or diurnal range depending on what coast it is on.

## Datum’s Boundary Applications

**Datum’s Boundary Applications**

**Notes:**
Boundaries to talk about in order of graphic enhancements: 
#MLW 
#MHW
A coastal home owner would have more land if living in CT compared to MA owners
#MLLW (chart datum)
#territorial sea related to MLLW (12 n. mi.)
#exclusive economic zone related to MLLW (200 n. mi.)

## TIDES SUPPORT TO NAUTICAL CHARTING

**TIDES SUPPORT TO NAUTICAL CHARTING**
**HYDROGRAPHY APPLICATIONS**

**HEIGHTS ARE REFERRED TO MHW**

**SOUNDINGS ARE REFERRED TO MLLW**

## Summary

_**Tidal datums**_** are based on a phase of the tide (ex. MHW, MLLW).**
**Station datums are based on a 19 year mean called an National Tidal Datum Epoch (NTDE).**
**Tide stations are referenced to bench mark system for stability checks & long term maintenance.**
**Datum applications: PORTS, chart depths , marine boundaries, hydrographic surveys, dredging, storm surge, modeling, wetland restoration, etc.**

## Data Set Description

- Quantity
- 	3,400 Stations
-   		    (Multiple Bench Mark Sheets)
- Media
- 	1” & 3 Notebooks
-    Approximately 62,400 pages
-    Organized by State

**Notes:**
Quantity:
      Hourly & Daily Means   25 entries/day * 365 days = 9,125 entries/yr
      Max/Min & Ann Mean    7 entries/month * 12 months = 84 entries/yr 
       9,209 entries/yr * 1,400 yr = 12,892,600 entries

       Pages of data = 2 page/month * 12 month/yr *1400 yr = 33,600 pages

MEDIA:
      Bound Books  -  two formats show in minute
      Tabular Pages   -  Daily Sheets  - 1 values per day with monthly mean 
                                -  Tri-Daily  3 values per day with daily, monthly means
                                -  Hourly Printouts - most of the 1960 - 1969  years of data
MICRO FICHE:
       most of the books completed in mid 70’s - not of good quality
	upside down
     	not in focus
       possible use only as emergency backup
ALL DATA LOCATED in Silver Spring

## Required Rescue Activity

- Scan and index bench mark sheets
- Preferred PDF images
- WSSRD accessibility

**Notes:**
SCAN:  Propose scanning original documents and have data keyed from images
	Reduce risk of damage to the bound books
	Provide rapid access to any user that would like to see originals
              NOT scan recent hourly data sheets
              Scan the old daily sheets
 	one value per day & monthly mean
	NOT in bound books, loose sheets with fastener
	scanning them would provide easy access
	NOT key daily sheets
KEY: 
QC:  using hourly data, compute means, & extremes

If contractor is interested, GLERL has developed FORTRAN programs for keying the data under an ESDIM project for the 5 master gauges on the lakes and the Buffalo gauge.  They have currently finished entering the data from Harbor Beach gauge & Ludington gauge.  

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## Projected Costs

- 1 COTR 	(80 hrs. @ $46.75)	$3,740
- 1 Preparer	(200 hrs. @ $20.21)	      4,042
- 2 Reviewers (800 hrs. @ $20.21)     	16,168
- Scanning (62,400 x 2 pages @ $1.00)	124,800
- Indexing (2 fields/image @$0.06)               7,488
-    Total		$156,238

## The End