Surveying Services for the Coastwide Reference Monitoring System (CRMS) RSIQ 2503-27-01

ENCLOSURE 1
SCOPE OF SERVICES
ELEVATION SURVEY UPDATE OF COASTWIDE REFERENCE MONITORING
SYSTEM (CRMS) STATIONS AND ASSOCIATED SECONDARY MONUMENTS
1. INTRODUCTION
The Coastal Protection and Restoration Authority of Louisiana (CPRA) requires surveying
services in order to update Coastwide Reference Monitoring System (CRMS) station
elevations. This comprehensive coastwide survey effort includes updating elevations of all
active monitoring stations including stations at 382 CRMS sites and in 11 project areas
(Figure A-1; Tables B-1, B-2, B-3 and B-4). The intent is to survey all stations in the same
year with field work beginning as soon as duck hunting restrictions allow in the winter to
be completed before peak hurricane season in late August 2027.
In order to accomplish the survey, elevations of secondary benchmarks must be updated
and a GPS network solution applied to the entire coastal zone. This coastwide survey effort
was previously performed in 2014 and 2021. This effort is effectively a repeat of the 2021
coastwide CRMS survey which utilized 173 GPS benchmarks (Figure A-2, Tables B-1, B-
2 and B-3) including 54 CRMS Rod Surface Elevation Table (RSET) stations set up as
GPS benchmarks for the first time in 2021. High precision surveys of the 53 CRMS RSET
benchmarks that remain active stations will be repeated as part of this survey effort and a
report on subsidence of Secondary Monuments and RSET rods will be a required
deliverable.
The surveying consulting company hereafter referred to as the "Contracting Party", will
perform the specified services according to this Scope of Services.
2. LOCATION
CRMS sites are distributed across coastal Louisiana with sites in every coastal basin and
marsh type (Appendix A, Figures A-1 and A-2; Appendix B, Tables B-1, B-2, B-3 and B-
4). Access routes and recommended boat type will be provided to the Contracting Party.
Routes have been agreed to by landowners and are to be followed precisely unless
otherwise directed by the landowner.
3. SCOPE OF WORK
The Contracting Party shall perform all surveying necessary to complete the tasks outlined
in the following subsections.
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3.1 Permission and access
Permission to access property for surveying activities shall be the responsibility of the
Contracting Party. CPRA has previously obtained land rights with each landowner
where the CRMS site has been established; however, these agreements specify that
notification shall be given to the land owner prior to accessing the property. Rights of
entry to privately owned property must be respected by all CPRA contractors. Failure
to adhere to the above stated CPRA policy will be considered grounds for termination
of the contract. Contact information for each individual CRMS site is provided in
Appendix C of this document. These individuals are to be notified each time the
Contracting Party visits the property except where advance notice has been given for
consecutive day visits. Access restrictions by many landowners begin during hunting
seasons; the Contracting Party must negotiate access restrictions with the landowners
and accommodate schedules, accordingly. Some landowners require access permits
including LDWF Wildlife Management Areas and federal National Wildlife Refuges.
3.2 General
The work to be performed by the Contracting Party consists of furnishing the
equipment, supplies, labor, and transportation, including boats and fuel, needed to
complete the work outlined in this scope. All materials and services not expressly
called for in this scope of work shall be provided by the Contracting Party at no increase
in cost to the CPRA.
Data collected at CRMS boardwalks capture soil formation processes including vertical
accretion and surface elevation change at millimeter scale. These processes have been
measured repeatedly at the same location with the same equipment for almost 20 years.
All of the area within and around CRMS boardwalks is occupied by active monitoring
stations that must not be disturbed. Surface elevation change is measured relative to
an RSET rod driven to refusal located in between the parallel boardwalk sections.
Vertical accretion is measured relative to feldspar marker horizons from stations that
flank the boardwalk on all sides. It is critical that the marsh surface is not disturbed
during this survey.
All work must be performed from the CRMS boardwalks without disturbing the marsh
surface around the boardwalk. The Contracting Party will need at least one 10 ft plank
to span the distance between the parallel boardwalks (Figures A-8 and A-9). There
shall be no walking on the marsh within a 30 foot buffer zone around the boardwalk
except at the access point of the boardwalk. Vegetation must be left intact. It can be
pushed to the side as needed to access stations but must not be cut or removed.
The access point is marked by a 3" PVC pipe with a yellow cap. The PVC pipe at the
opposite end of the boardwalk has an orange cap. The only acceptable way to access a
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CRMS site is from the end of the boardwalk marked with a yellow cap. Boats shall
park perpendicular to the boardwalk at the access point. Pulling alongside the
boardwalk in a parallel fashion is not allowed because accretion stations will be
permanently damaged.
The goal is to accomplish all of the field work required for the 2027 CRMS station
elevation update before peak hurricane season (before 8/31/2027). It is recommended
that a majority of the work occur in the winter and spring in order to avoid summer
thunderstorm delays and before vegetation interferes with surveying. In the 2021
surveying effort, surveyors had a difficult time collecting high precision data in
swamps. Ultimately, a local GPS network had to be constrained around the Maurepas
Swamp. It is recommended that swamp sites be surveyed early in the year.
All field work shall be completed by August 31, 2027. Draft and final versions of
reports shall be delivered by March 31, 2028.
3.2.1 Datums and Accuracy:
Horizontal Datum
Units: Units of XY data (meters)
Coordinate System: Universal Transverse Mercator (UTM) Zone 15 N
Datum: North American Datum 1983 (NAD 83)
Vertical Datum
Z_Unit: feet
Datum: NAVD 88 Geodetics GEOID12B
Geodetic Reference System 1980 (GRS 80)
Vertical Accuracy
0.5 to 2 cm for Survey Benchmarks (Secondary Monuments)
<1 cm for high precision monuments
3-5 cm for RTK
3.3 Deep Rod Secondary Monument Network Solution
The Contracting Party shall perform static GPS surveys at all benchmarks required to
create a GPS network plan as described in Section C of the CPRA Survey Standards
document (CPRA, 2019; T Baker Smith, 2022). In 2021, 173 benchmarks were utilized
to constrain a coastwide GPS network (Figure A-1, Table B-1). The same benchmarks
can be utilized or alternate benchmarks may be recommended by the Contracting Party
if better monuments are available.
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In 2021, 54 CRMS sites were incorporated into the Secondary Monument network. Of
those, 32 were established as benchmarks at 2 cm resolution and 22 were established
as high precision, sub-cm benchmarks. Two of the CRMS RSET benchmarks have
been compromised leaving 52 CRMS RSET benchmarks active on the landscape to be
re-surveyed to the same precision as was performed in 2021 (Table B-1).
TBM's may be used when benchmarks are not available. Where possible, CRMS
RSET rods are to be established as benchmarks in lieu of temporary TBMs.
Benchmark elevations are to be modeled into a numerically constructed GPS network
as was performed in 2014 and 2021. See Section F of the CPRA's 2019 Standards of
Practice for Contractors document (CPRA 2019). A network adjustment report will be
required (T Baker Smith, 2022).
Deliverables for static GPS monument observations are listed in Section H, and the
standard forms and example documents are shown in Section J of the referenced survey
standards document (CPRA 2019). These deliverables will include GPS monument
information datasheets, GPS session schedules and GPS log sheets, field notebook
records, photographs, final adjusted GPS data, and digital GPS data in a RINEX format.
Note, the monument datasheets slightly differ from the example provided in the 2019
Standards of Practice document in that the UTM NAD 83 coordinates in meters are
also required in addition to geodetic and lambert coordinate (LSZ) positions.
Secondary Monument datasheets must be updated with data collected from this survey
(Figure D-3). In the 55 cases where the CRMS RSET rod serves as a secondary
benchmark, the datasheets shall additionally include a 'top of rod' and 'top of collar'
elevation (as described in Section 3.5.2 and Figure D-6) and shall denote the accuracy
of the survey after the Date of Survey in the following manner: "Survey Accuracy: 2
Centimeter" or "Survey Accuracy: Sub Centimeter".
3.4 High-Precision Static GPS Observations on RSET Rods
In 2021, a subset of 22 CRMS sites were surveyed to sub cm resolution. This work
will be repeated on the same RSET stations as part of this scope of work (Figure A-1
and Table B-1). These static GPS observations will consist of three separate data
collection sessions at each RSET Rod. Each GPS session will have a minimum
duration of 6-hours separated by periods of approximately two days (48 hours) at each
RSET Rod. For example, the Contracting Party shall collect static GPS observations
for 6-hours and will return to this RSET rod a minimum of 48 hours later for a 2nd 6-
hour session followed by a 3rd 6-hour session at least 48 hours after the 2nd static GPS
session has concluded. The purpose of these replicate (3 sessions) and long duration
(6-hour) static GPS observations are to attain sub centimeter level elevation accuracies
at the selected RSET rods. Separation between observation periods are set so the
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observation series are collected under differing atmospheric conditions and different
satellite constellations.
NOTE: This procedure slightly deviates from Section F of the 2019 Standards of
Practice document and simply requires a 3rd GPS session and a minimum of 6-hour
sessions to achieve sub centimeter level elevation accuracies. Therefore, portions of
this task can be combined with the task listed in Section 3.3 by recording static GPS
observations for at least 6-hours and requiring a 3rd data collection session at the
selected RSET rods.
Monument data from the 2021 network solution will be provided to the Contracting
Party for comparison to monument elevations established by this survey. A report that
describes subsidence of the monuments will be required (Section 5.3).
3.5 Real Time Kinematic (RTK) Surveys
RTK will be utilized to update elevation of all active CRMS hydrology and RSET
stations in addition to a handful of remaining project specific stations. Ancillary marsh
and water bottom elevations will also be collected at each CRMS hydrology station
while on site.
Most CRMS sites have the same set up with one hydrology station and one RSET
station to be surveyed. There are special cases where there is no hydrology station or
RSET rods have been compromised and removed. A complete list of stations to be
surveyed can be found in Tables B-2, B-3 and B-4 and special cases are called out in
Tables B-5 and B-6.
If propagation errors occur due to multipath distortion, conventional elevation surveys
may be performed as long as TBM(s) have been established using RTK methods. The
TBM must be within the 3 mile radius of a LCZ GPS network Deep Rod Monument or
another TBM that has been surveyed into this network. Where possible, existing
CRMS RSET rods shall be used as TBMs. In addition, a level loop (single-run
leveling) must be performed to minimize the effects of elevation misclosure when using
optical instruments.
3.5.1 Hydrologic Station (H0#) Data Collection on Support Poles
Marks on the continuous recorder (CR) and staff gauge (SG) support poles are to be
surveyed into the LCZ GPS network by the Contracting Party. The Mark (or nail) is to
be the primary elevation point for each CRMS hydrology station. Elevations will also
be collected from the tops of the wooden 4x4" CR and SG posts as well as water surface
and water bottom elevations near the station (Section 3.5.3).
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Hydrologic stations (H0#) consist of two 4"x4" timber posts driven to resistance in an
open body of water with nails driven into one side of each post (TBM). One of the
4"x4" posts functions as the support pole for a continuous recorder (CR, Figures A-3,
A-4, and A-5) while the other 4"x4" posts functions as the support pole for a staff gauge
(SG, Figures A-4 and A-6). The nail constitutes the "mark", or TBM, that CPRA
utilizes to convert the water-level data to the NAVD 88 datum (ft). The top of the
4"x4" timber posts shall be surveyed and measurements shall be obtained to calculate
the NAVD 88 (ft) elevation of the nail. The nail shall also be surveyed as a check as
outlined in section P of the 2019 Standards of Practice manual. Data collected shall be
sufficient to complete the spreadsheet and data sheets in Appendix D (Figure D-1 and
Figures D-4 and D-5). Survey notes and photos shall follow the detail outlined in
section P of the 2019 Standards of Practice manual.
NOTE: The "nail" has been established in each post/board; therefore, another one shall
not be established without approval from a CPRA employee.
NOTE: While at the site, verify that the elevations from the two adjacent CR and SG
stations make sense. Tape down from elevations collected on the CR and SG posts to
water level and verify that all measurements taken from each station are reasonable
relative to one another. Water level can change quickly in tidal marshes so it is a good
idea to get water elevation measurements at about the same time as all other elevations
are recorded from each CR and SG post.
Special Cases in Hydrology Setups
USGS ran ten CRMS real-time stations from program inception through July 2026
when they were converted to typical CRMS non-real-time stations. The USGS
platforms are larger than typical CRMS hydro stations with four posts and room for
solar panels and transmitters (Figure A-7). In most cases, the new, non-real-time
equipment was attached to the USGS real-time platform. Site specific details for USGS
real-time platforms are provided in Appendix E.
Floating marsh sites are set up differently than attached marsh sites. At each of the 33
floating sites, there is an open water station (-H01) that is to be surveyed as described
above. There is also a boardwalk that goes into the marsh where a floating marsh water
level recorder (-M100) is located. M100 stations measure inundation of the floating
mat and are not surveyed to datum. Staff gauge posts have been added to the floating
marsh sites at the boardwalk near the -M100 station and those need to be surveyed for
the first time. Survey points to be collected on floating marsh staff gauge posts include
the Top of Post, Mark (nail), water bottom elevation, and the elevation of the floating
mat at the time of survey. The staff gauge data sheet (Figure D-1) and marsh elevation
data sheet (Figure D-2) can be utilized for these floating marsh staff gauge surveys.
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Previous analyses revealed that seven CRMS hydro stations were redundant (meaning
daily mean water level and salinity were statistically the same). In those cases, one
hydro station provides data for two CRMS sites (Appendix B, Tables B-2, B-4 and B-
5). Stations that have a surrogate hydrology station are identified in CRMS as -H0X
stations. There is no hydrology equipment to be surveyed at -H0X stations.
3.5.2 Rod Surface Elevation Table (RSET) Stations
Survey points on CRMS RSET stations (E0#) include the top of the 9/16" stainless
steel rod and the collar mounted to the rod (Figures A-8, A-9, A-10 and A-11). In order
to access these stations, boards at least 10' long should be placed across the two
boardwalks to span the distance between without disturbing the marsh surface. Survey
notes and photos, similar to section K of the 2019 Standards of Practice manual shall
clearly define the top of the rod and measurements shall be obtained from the top of
the collar at the number "1" position to the top of the rod. Data collected shall be
sufficient to complete the data sheet in Appendix D (Figure D-1 and Figure D-6).
There are 347 RSET rods included in this survey (Appendix B; Tables B-2 and B-3).
Due primarily to erosion and land loss, RSET rods from 17 CRMS sites that were
previously surveyed do not require surveys in 2027 (Tables B-2, B-3 and B-6). Active
hydrology stations remain at eight of the 17 sites that no longer have RSET rods (Table
B-4) and those hydrology stations and nearby fringe marsh do need to be surveyed (see
Section 3.5.4 below).
As described in Section 3.4 above, 52 RSET rods that were used as benchmarks in the
2021 survey effort remain intact and available for the 2027 survey effort (Table B-1).
The remaining 295 active RSET rods are to be surveyed using RTK precision and
methodology.
3.5.3 Marsh Surface Elevation at the Boardwalk
At CRMS boardwalks, marsh elevations will be collected from ten locations; two from
each corner of the boardwalk that surrounds the RSET station and two from the marsh
adjacent to the RSET station (Figure A-8).
In most marsh types, one marsh elevation per location is sufficient (one from each
location identified in Figure A-8). However in clumpy, Spartina patens (saltmeadow
cordgrass) marshes where the vegetation can be much higher within clumps of
vegetation than on the mud surface between clumps of vegetation, two observations are
required from each location: one to be taken within the clump of Spartina patens and
one to be taken from the mud adjacent to/between the clumps of grass. In this case, 20
elevation shots are to be taken at CRMS boardwalks. Marsh elevations are to be
recorded on the datasheet presented in Figure D-2.
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In general marsh surface with respect to elevation surveys is defined as "where the
survey rod is resting among living stems or is supported by soil containing living roots."
In order to get a consistent reading it will often be necessary to move stems in some
marsh vegetation where stem density is extremely high.
3.5.4 Marsh Surface Elevation in Fringe Marsh
At some CRMS sites where significant erosion has occurred, the RSET rod has been
removed and only hydrology monitoring continues. The Contracting Party will survey
marsh elevation in the fringe marsh near these eight sites (Tables B-2 and B-6 and
Figures B-1a to B-1g). Marsh elevation will be collected from within living vegetation
at ten locations in homogenous marshes and 20 locations in clumpy Spartina patens
marsh as described above. There are not specific station locations to be surveyed but
rather the intent is to capture elevation of nearby remaining vegetation to be used in
inundation depth calculations.
At CRMS0302, the RSET rod has destabilized and has been removed but vegetation
stations remain intact (Table B-6). Here, the Contracting Party will survey the
hydrology station and will also install a TBM that CRMS data collection contractors
can use to run a loop with a laser level.
3.5.5 Water Bottom Elevation
Ancillary water bottom elevation data are to be collected opportunistically at each
CRMS hydrology station and along select waterways in between CRMS stations
(Appendix F). The purpose is to maximize the impact of the CRMS dataset by
providing CPRA's Coastal Master Plan modelers information necessary to
contextualize CRMS hydrology data.
The locations to be surveyed include water bottom elevation at the base of each active
CRMS hydrology station along with the transition from water bottom to vegetated
surface where possible. The X, Y, Z deliverable format is included in Appendix D
(Figure D-7).
NOTE: Surveying CRMS stations is the primary objective of this scope and the water
bottom surveying is ancillary. The Contracting Party should utilize whichever boat
type is required for the primary objective. Where large boats are needed, it may not be
possible to also survey transition to vegetation.
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Sonde to Shore
Survey water bottom elevation at the base of each hydro station. In small channels (<
20 feet wide), also survey a cross section of the waterway from vegetated marsh
surface, across the waterway to the vegetated surface on the opposite bank collecting
water bottom elevations every five feet. In larger bodies of water, survey water bottom
from the CRMS station to the nearest edge and up onto the vegetated surface as
equipment allows.
Up and Down Stream
When stations are located in bayous, canals and other channels, survey water bottom
elevation in the center of the waterway up and down stream for 100 feet in each
direction from the hydrology station taking an elevation every ten feet. In large water
bodies, orient the 200 foot transect along the typical flow path (i.e. from inshore
towards offshore) and take elevations every ten feet.
While Traveling between CRMS Sites
The CMP team has identified locations where channel bathymetry data is lacking and
any and all water bottom elevations would be useful for improving CMP assumptions
(Appendix F). If time in the field allows while surveying CRMS stations, also survey
water bottom elevations at the center of the channel every 100 ft in locations identified
in Appendix F.
3.6 Methodology Meeting
A meeting will be conducted between CPRA and the Contracting Party to discuss
methodologies and details of the survey prior to starting field work.
4. LASARD
CPRA maintains the Louisiana Sand Resources Database (LASARD) Program to help
facilitate the identification and management of nearshore, offshore and riverine
sediment resources. The LASARD database is also used to manage, archive, and
maintain geological, geophysical, topographic, bathymetric, geotechnical and other
related data pertaining to the exploration of sand/sediment in various environments
(Kahlil et al., 2022).
The Contracting Party shall follow the LASARD Standard Operating Procedures for
Geo-Scientific Data Management with respect to data collection and reporting
guidelines for the survey investigation and all other data collection efforts. This
Standard Operating Procedure, corresponding attribute specifications, and GIS
templates can be obtained from the CPRA website with the link provided in Section 6.
For all questions pertaining to the LASARD program, please contact Syed Khalil at
225-342-1641 or syed.khalil@la.gov.
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5. DELIVERABLES
5.1 Bi-Weekly Report
Reports will be required on a bi-weekly basis and shall include: (1) sites and
benchmarks visited, (2) status of work completed at each site, and (3) any problems or
encounters with landowners or lessees. The bi-weekly reports shall be sent to the
CPRA Task Manager (Leigh Anne Sharp, LeighAnne.Sharp@la.gov).
5.2 Survey Reports
A survey report shall be generated for each CRMS site to be delivered in PDF format.
The report will include but is not limited to a title page with PLS stamp and signature,
a methodology report, and the deliverables listed in Section 3 of this Scope of Work.
These deliverables will include:
a) Data Sheets - GPS Monument, Continuous Recorder (H0#), Staff Gauge (H0#),
and RSET (E0#)
b) GPS Session Schedules and GPS Log Sheet
c) Tables and Excel Spreadsheets - Continuous Recorder Gauge, Staff Gauge (include
gauge correction factors), and RSET (E0#)
d) Field Notes That Include Drawings
e) All GPS Data Will Be Provided in a Digital Format Including Final Adjusted GPS
Data
f) Digital Static Survey GPS data in a RINEX format
g) All photographs taken at the site in a zip file
NOTE: Photos in the survey report shall be photos of the actual CRMS stations at the
time they were surveyed and not stand in, generic photos.
NOTE: Before deliverables are finalized, draft versions are to be sent for review and
comment.
The draft and final versions of reports shall be delivered to Leigh Anne Sharp Coastal
Resource Scientist Manager of CPRA in the Lafayette Regional Office who will serve
as Task Manager for this contract. The address is as follows:
Coastal Protection and Restoration Authority
PO box 62027
Lafayette LA 70596-2027
Physical Address:
635 Cajundome Blvd.
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