Bathymetric Elevations for Lake Apopka, 2007-8

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Metadata_Reference_Information

Identification_Information:

Citation:

Citation_Information:

Title: Bathymetric Elevations for Lake Apopka, 2007-8

Online_Linkage:

\\palfile\sjrx\ES\Apopka\active_projects_2008\bathy_tracking_2007_2008\data_fr_morgan\survey_data\all_data_sjrharn

Description:

Abstract:

Morgan & Eklund, Inc. was contracted by the St. Johns River Water Management District to perform a bathymetric survey of Lake Apopka located in Lake and Orange Counties, Florida. The work consisted of setting horizontal and vertical control points for RTK/GPS base stations around Lake Apopka, running bathymetric survey transects at approximately 2000' intervals N-S and E-W and developing a bottom elevation contour map from the data. Additionally, the location of muck bottom areas was mapped utilizing the high frequency fathometer records. Elevation of the points was originally collected in NGVD 1929 vertical datum. NAVD 1988 elevations were computed from the NGVD 1929 values using VERTCON/CORPSCON software. Elevation values for both vertical datums are included in the attribute table. Note: The metadata for this layer was constructed from information contained in the "Lake Apopka Bathymetric Survey Report, February 2008".

Purpose: Bathymetric elevation measurements for Lake Apopka.

Supplemental_Information: "Lake Apopka Bathymetric Survey Report, February 2008"

Time_Period_of_Content:

Time_Period_Information:

Range_of_Dates/Times:

Beginning_Date: 200712

Ending_Date: 200803

Currentness_Reference: ground condition

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Keywords:

Theme:

Theme_Keyword: bathymetry

Place:

Place_Keyword: Lake Apopka

Place_Keyword: Florida

Data_Quality_Information:

Lineage:

Process_Step:

Process_Description:

The bathymetric survey was performed in accordance with the U.S. Army Corps of Engineers Manual for Hydrographic Surveys for a Class I survey.
Our survey boats were calibrated for draft, squat and settlement and our survey fathometers were calibrated utilizing a "bar check calibration" as delineated in the USCOE Manual. In addition to the "bar check calibration", thirty (30) bottom calibration points were measured throughout a variety of lake bottom types with RTK/GPS for use as additional sounding calibration points. The elevation of each of these calibration points was measured at the beginning of the project using a survey rod with an 8" diameter aluminum disk mounted at the bottom and reading the elevation data using RTK/GPS. Some of the areas chosen for measurement consisted of fluid mud and did not yield the expected correlation with the fathometer soundings. Also, a 1000' segment of the last profile line of the day was re-run at the beginning of the next day to provide for a second independent check on our data collection and reduction methodology. To verify the boats horizontal positioning, a point was surveyed in by static GPS near the District's boat ramp to use as a horizontal position check prior to the survey on a daily basis. Before starting the data collection process, Morgan & Eklund, Inc. had a representative of Odom Hydrographic Systems visit the project site and review the Odom dual frequency fathometer setup, calibration and data collection procedures to determine if anything can be done to enhance the low frequency fathometers ability to map the muck layer thickness. Sounding and DGPS position data was collected and stored simultaneously utilizing Hypack Navigation Software. The proposed theoretical profile line locations was pre-programmed into the Hypack Navigation computer which provided a steering indicator for the boat operator during the data collection. Sounding and position data was collected at 10' intervals along profile lines spaced at 2000' intervals N-S and E-W together with selected intermediate profile lines at 1000' intervals.

Spatial_Data_Organization_Information:

Point_and_Vector_Object_Information:

Spatial_Reference_Information:

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Altitude_Datum_Name: NGVD 1929 and NAVD 1988

Altitude_Distance_Units: feet

Entity_and_Attribute_Information:

Detailed_Description:

Entity_Type:

Entity_Type_Label: BATHY_APOPKA_2008_PTS_ME

Attribute:

Attribute_Label: FID

Attribute_Definition: Internal feature number.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are automatically generated.

Attribute:

Attribute_Label: Shape

Attribute_Definition: Feature geometry.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Attribute:

Attribute_Label: ID1

Attribute_Definition: 1-based identification number for each point

Attribute:

Attribute_Label: ID

Attribute_Definition: Original ID number assigned by Morgan & Eklund

Attribute:

Attribute_Label: NORTHING

Attribute_Definition: Northing (Y) in UTM zone 17 meters HARN

Attribute:

Attribute_Label: EASTING

Attribute_Definition: Easting (X) in UTM zone 17 meters HARN

Attribute:

Attribute_Label: DESCRIPT

Attribute_Definition: Feature description

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: EC

Enumerated_Domain_Value_Definition: Edge of concrete (?)

Enumerated_Domain:

Enumerated_Domain_Value: EOW

Enumerated_Domain_Value_Definition: Edge of water

Enumerated_Domain:

Enumerated_Domain_Value: GB

Enumerated_Domain_Value_Definition: Grade break

Enumerated_Domain:

Enumerated_Domain_Value: MUCK

Enumerated_Domain_Value_Definition: Muck

Enumerated_Domain:

Enumerated_Domain_Value: NG

Enumerated_Domain_Value_Definition: Natural ground

Enumerated_Domain:

Enumerated_Domain_Value: SAND

Enumerated_Domain_Value_Definition: Sand

Enumerated_Domain:

Enumerated_Domain_Value: SNDG

Enumerated_Domain_Value_Definition: Sounding

Enumerated_Domain:

Enumerated_Domain_Value: TOB

Enumerated_Domain_Value_Definition: Top of bank

Enumerated_Domain:

Enumerated_Domain_Value: TOE

Enumerated_Domain_Value_Definition: Toe of levee

Enumerated_Domain:

Enumerated_Domain_Value: TOP

Enumerated_Domain_Value_Definition: Top of levee

Enumerated_Domain:

Enumerated_Domain_Value: VEG

Enumerated_Domain_Value_Definition: Vegetation

Attribute:

Attribute_Label: ELEV_NAVD8

Attribute:

Attribute_Label: ELEV_NGVD2

Metadata_Reference_Information:

Metadata_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: St. Johns River Water Management District

Contact_Position: GIS Manager

Contact_Address:

Address_Type: mailing and physical address

Address: 4049 Reid Street

City: Palatka

State_or_Province: FL

Postal_Code: 32177

Country: USA

Contact_Voice_Telephone: 386-329-4500

Hours_of_Service: 8 AM to 5 PM ET