D~~~~al.Ll ~ ~~ COMMISSIONERS' COURT AGENDA REQUEST PLEASE FURNISH ONE ORIGINAL AND NINE COPIES OF THIS ~: REQUEST AND DOCUMENTS TO BE REVIEWED BY THE COURT. MADE BY: Commissioner Williams OFFICE: Precinct Two MEETINfG DATE: Feb. 8, 2010 TIME PREFERRED: 9:15 a.m. SUBJECT: Presentation on technology and methodology of Acoustic Bathometry used'in surveying fresh water lakes such as Flat Rock Lake. ' EXECUTIVE SESSION REQUESTED: (PLEASE STATE REASON) NAME OF PERSON(S) ADDRESSING COURT: Commissioners Williams & Jimmy Saunders of Branchwater Services, J3 S, Inc., Georgetown, Texas. ' ESTIMATED LENGTH OF PRESENTATION: 20-30 minutes. IF PERSONNEL MATTER - NAME OF EMPLOYEE: Time for submitting this request for Court to assure that the matter is posted ' in accordance with Title 5, Chapter 551 and 552, Government Code, is as follows: Meeting scheduled far Mondays: THIS REQUEST RECEIVED BY: THIS REQUEST RECEIVED ON: 5:00 P.M. previous Tuesday. @ ' All Agenda Requests will be screened by the County Judge's Office to determine if adequate information has been prepared for the Court's formal consideration and action at time of Court Meetings. Your cooperation will be appreciated and contribute towards you request being addressed at the earliest opportunity. See Agenda Request Rules Adopted by Commissioners' Court. BranchWater Services q6oi West Highwa~29 Georgetown, TX ~s62s December 29, 2009 MEMORANpUM To: Mr. Les Boyd Freese and Nichols, Inc. Austin, Texas Subject: Survey of Kerrville Lake Impounded by Flat Rock Dam in Kerr County Purpose and As~umptions: The purpose of this memo is to offer comments regarding the potential acoust~c survey of Kerrville Lake, sometimes referred to Flat Rock Lake, upstream of Fla~ Rock Dam in Kerr County. The preliminary conclusions are based on limited informaCion and are subject to revision if new information becomes available. In order to assess the strength of the conclusions some of the assumptions used follow: • Kerrville Lake is a shallow, constant level lake contained within the primary banks of the Guadalupe River for a span of about 7,500 feet from Flat Rock Dam upstream to Legion Crossing Road and ranges from 300 to 1,200 feet in width. The Lake has approximately 120 surface acres and contains approximately 600 acre feet of water at an average depth of 5 feet and a maximum depth of approximately 14 feet. The dam is earthen with a concrete cap and accommodates a normal lake level spillway of about 160 feet in length. The Lake contains a bar just south of the center axis which has many small islands sometimes exposed over the length of the lake and one larger island of about four acres' about 2,500 feet upstream of the dam. The maximum current in the Lake is not exp~cted to exceed 1.0 knots (~45 cubic feet per second flow) except during flood events. • The Lake acoustic survey would encompass approximately 80 acres from the dam to about 1000 feet downstream of the Legion Crossing Road and cover all areas where depth exceeds 3 feet. The acoustic survey would be supplemented by a shoreline survey in order to approximate the bathometric features in shallow water. • Lake facilities suitable for monitoring of the acoustic survey (a location where data collection vessels can be visually monitored), and facilities suitable for launching sensor platforms (a boat ramp or natural feature usable as a boat ramp) made available to the survey crew. • Lake access for the sensor platforms (9 foot robotic vessel) and a survey boat (10 foot plastic punt with outboard motor), including access inside any security or safety barriers granted'to the survey crew. Survey Preliminary Plan: The plan is to provide a high quality survey of the bottom contour of the lake from below the Legion Crossing Road to the dam to support decision making and potential contracting for silt removal. For this purpose Branch Water Services would propose to conduct a survey with four principle parts: 1. A multi-beam (wide fan beam) sonar survey of the apparent lake bottom for depths greater than 3 feet. 2. A sub-bottom profiler (narrow beam, penetrating) sonar survey of the hard bottam of the lake beneath the silt for depths greater than 3 feet. 3. A GPS shoreline survey of the lake shore including exposed islands. 4. A side-scan (acoustic imagining) sonar survey of the lake bottom for depths greater than 3 feet. The multi-beam survey will provide data for a high resolution topographic representation of the lake bottam, the sub-bottom profiler will provide hard bottom data for a topographic representation of the native lake bottom below the sediment, the shoreline survey will improve the topographic representation of the lake bottom in shallow areas, and the side-scan survey will provide images of the bottom that will aid in the interpretation of features extracted in the multi-beam survey. The survey products would include a report of the survey, its accuracy and findings, and would include topographic representations of the lake bottom, native bottom and sediment. Survey Variables: The effectiveness and efficiency of a survey as described can be impacted by external conditions or by decisions regarding survey operations. For example if the lake contains obstructions such as fences, barricades or debris, the thoroughness will be reduced and the cost increased. Further if the customer desired the best precision and maximum coverage the accuracy will improve and the cost will increase. Survey Accuracy - The inherent accuracy of the BranchWater sonar surveys is driven by the accuracy of the position location of the moving sensors and the density of the survey points. The pos~tion location error is manifest in uncertainty of the exact location of the acoustic reflectibn from the bottom and the slope of the bottom over that area of uncertainty. BranchWater uses high precision GPS receivers mounted to the senor for position location and post processes the position data to ensure the best accuracy. This processing includes accounting for the motion of sensor platform including pitch, roll, and heading at each data point sample time. The GPS receiver is typically supplemented by local differential GPS corrections allowing accuracy equivalent to GPS land survey systems. Using only autonomous WAAS enhanced GPS without the local differential correction results in a relatively minor reduction in accuracy but with limited cost savings. The data density attributed error is manifest in the need to extrapolate from any particular data point to the nearby points. Lower data densities result in smoother feature representation, that is, longer extrapolation runs from one data point to the next, and the opportunity to smooth over a feature where no data points exist. The selection of a target data density should be driven by the desired accuracy of the data product, e.g. a topographical map. The desired accuracy of the data product should be driven by the ability to use the information gained. It serves no effective purpose to measure something to the nearest inch if the planned operation can only operate to the nearest yard. Or put another way, there is no point in searching for features three inches in diameter if the plan is to remove material with a 5 cubic yard bucket. Survey Operations and Schedule - There are five phases to any acoustic survey 1) planning, 2) mobilization, 3) data collection, 4) data processing, and 5) report preparation. All five phases are impacted by the size of the project and the accuracy desired but planning, data collection and data processing are most directly linked to the volume of data to be collected. Some of these activities can be conducted concurrently. Normally the team arrives on site the day before we "go in the water" to set up GPS and monitoring stations and acclimate the team with the environment. Operations are normally conducted in daylight hours covering 25 to 1000 acres per day and removing all equipment from the water at the end of each day. Second site visits are always a possibility but are not normal. A small project like Lake Marble Falls (135 acres, high accuracy) required 10 days to plan and mobilize, 3 days on-site for data collection, 10 days for data processing and 2 days for report preparation for a total of 5 work weeks. Survey Costs - Planning costs are driven by the size of the project and to a lesser extent the accuracy. The robotic vessel missions must be preplanned and to do this a detailed mapping of the estimated location and depth of the body of water must be created. Mobilization costs are driven by the amount of equipment to transport to the site, which is driven by the size and duration of the project, and the accessibility of the survey area. Data collection, processing and reporting are directly linked to the project size and accuracy. Preliminarv Pronosal for Kerrville Lake: Statement of W~brk - Conduct an acoustic bathometric survey of the lower 6,500 feet of Kerrville Lake ~here water depth is greater than three feet but provide estimates of the water depth to the shoreline including islands. Provide 2 foot centered depth measurements for both the apparent bottom and the native bottom below the sediment in the local state plane coordinates. Provide a report of findings and error estimate to accompany the data. Provide assistance as needed in importing the data to the GIS application seleCted by the customer. Provide data to an accuracy suitable to render the data into topogr~phical contours in 1 foot increments (precision greater than or equal to 0.1 feet, accuracy 0.5 feet or better). Schedule - On-site within 2 weeks of authorization to start unless otherwise agreed. Data collection 3 to 5 days on-site unless extended by equipment problems. Data processing and report preparation complete within 3 weeks of data collection completion. Cost -$14,000 to $30,000 depending on detailed discussion and agreement on data density requirements and depending on lake access and obstruction conditions. The $14,000 estimate is based on no access or obstruction issues and an apparent average bottom data density equivalent to 15% of full coverage. ~ranchUl~ter s ~ ~~~ , Feb~uary 08, 20 f0 Informaiina inclnAeA herein is em~trolleJ unAer the hiterna~ional ~fr»flic i~~ Arms Rrgula(ions (I"fAR). Transfer to a forei~n prrxon ur enlitc requires an e~port liccnse from Ihe l'~.8. Slntc Ucpnr~menf prinr to fransfer. 08 February 2010 ITAR - J3S Proprietary 1 RranchUl~ter ~ ' Project Agenda ^ Branch Water Services Background - Women owned small business- established 2000 to conduct R&D for the US Navy ^ Overview of advanced sensors and data collection platforms ^ Discuss sonar technologies ^ Outline autonomous vehicle capabilities ^ Discuss the planning, data collection, processing and products ^ Discuss lake survey considerations 08 February 2010 ITAR - J3S Proprietary 2 1 aranchUl~ter ~, :~. Hydrographic Survey System • Mission Surveys ^ Bathymetric J Features & Inspection iJ Before and After Volumetric ^ Object Location and Recovery ^ Hazard Location Mapping ^ Chemical/Biological Mapping • Sensors J Side-Scan Sonar ^ Profiling Sonars J Multibeam J Sub•Bottom Contouring U Echo Sounding ^ Acoustic Camera ^ ChemlBio Probes or Samplers ^ Differential GPS (DGPS) • Platforms ^ Piloted Craft ^ Radio Controlled Craft ^ Autonomous Vehides J Light Craft :] Mini•Vehicles 7 Full Mission Vehicles 08 February 2010 ITAR - J3S Proprietary 4 t3r~nchUl~ter Mission - Volumetric Silt ._ ~ ~ ~_~~_ S u rvey ~ TM:~ ~ - - ,, . 08 February 2010 ITAR - J3S Proprietary 5 2 ~~ ~ ~,,~~ .+~, .,., ~ „ ~` ' ~•, ~ ,=,'~ ~ . f3r~nchUleter ° ~ ~"~ Multi-Beam - Apparent Lake Bottom 9 3 t3ranchUleter Survey Platform ~ ~ _~ 08 February 2010 ITAR - J3S Proprietary 12 4 ~ranchUl~ter ` ' ' ° `~' ~ '` Special Vehicie Advantages • Traces a more accurate track with a more stable sensor platform and with a more precise DGPS location ^ Reduces manpower needs and risks, and lowers the cost of field survey operations • The ability to intelligently collect bathymetric, hydrographic, and water quality survey data without "holes" or "overlap" • The versatility to support various specialized sensor deployment options • The capability to accurately and precisely repeat a survey multiple times over an extended period of time to allow exact comparison of data , ; ,~,.*~~ OS February 2010 ITAR - J3S Proprietary 14 Br~nchUl~ter - ~.. ~ , 15 Mission Planning (~60 Acres, 8 ft deep) 5 arenchUleter _ , -,~,~ _ Data Collection ~ ~~ 4 ~ ~ ~ ~ ~ ~ ~ ~~; ~ ~ ~ ~ ~ : ~~ 4 ~ ~ ~- .. ~ ~. : ~r. , e : ~ ~ y~. .~ , ~. ~. ~~~ ~~ ~ ~ ~~~.~ .~f.~.. . i..r. 08 February 2010 ITAR - J3S Proprietary 17 6 BranchUlat~r granch Water Data Processing .~ s V>n.r-~r~>,~ & Products ~ Dense bottom and sub-bottom surFace data set • Derive desired secondary products - Grid fixed data points - Elevation contours - Colorized 3D visualizations - Colorized & registered map or photo overlays OS February 2010 ITAR - J3S Proprietary 19 BranchUlet~r ~~ ~~~~~`Y~°`~~~~` Lake Considerations • Driving considerations ' - Depth & depth variation - Obstructions (docks, fences, barriers, debris, stumps, fallen timber, etc.) - Product precision (e.g., % bottom coverage) - Delivered product (form and format requirements) • Other considerations - What portions are most important (e.g., first 100 yards up stream of the dam) - How will data be used (e.g., spec. in dredging contract) - Water flow surface velocity QS February 2010 ITAR - J3S Proprietary z~ 7 f3ranchUleter ~ ` "':: ~: ` Lake Worth L (~44 acres) OS February 2010 ITAR - J3S Proprietary 26 t3ranchUl~ter ~ ' ° "`';' Lake Worth L (Apparent Bottom) - -~ ~ ~ ~ ~ ~ ~ i:~~ ~ ~p'~ ~ '_ ~ k \ ti ~ ~ ~ ~ ~ . ~ Y ~yti ~ t ~ V ~ , . . ~ " ~~~ ~. . ~~ ~ , , r ~~ ~ ~r ~~ ~a 1 ~ -'a~ . ~ [ _ ~~ I ~ ~ '~ I a ~ ~ ~~. _ ~ ~ ~ l~ ( ~ q ~ ~ i . ~ ~, E b~ f l 1 ~ ~ ~ ~ ~ p~ ~ . . 1 r' ~ ~ ~{ ] ~ .~ ~~ \ ` ~ ~f ~ ~ ~ ~ I ~ ~y , ~ ' \\ ' . . p \... ~ I '~ ~-. \ ` _ , i" ~'Ip r ~~~ ` ~ ,. ~ 08 February 2010 ITAR - J3S Proprietary 27 $ t3ranchUleter ~ , ~~::,, Lake Worth L (Sub-Bottom) 08 February 2010 ITAR - J3S Proprietary 28 ~ranchUleter . , ~, 08 February 2010 Lake Worth L (Silt) ITAR - J3S Proprietary 29 9 sranchUloter s . ~, ~ , . 08 February 2010 32 ~.F-~F.~;~ a ~ ,~ ~ Questions? ,~'~ ~ ~ ~~ ~~ ~ ~ ~ .: , ~ ~, . _ . ,~ ~ :. _~~~,~~.4~~ _ . ~: . , I _ _; _ ~.. , . . J, . ~ , ,.,:~.; "~,i ' ~ _ ~3 Technical Point of Contact: Jimmy D. Saunders 9601 W Hwy 29, Georgetown, TX 78628 Phones: Office - 512-762-8559, Fax - 512-259-6001 Email: a~~:~rk.~ae.srsc4e;s~c~j3~ ,. ; Web: vrw~a,k~r-a~~c~~=~~~~erservi~.s:.~.c~ita~ 10 Flat Rock Lake be surveyed & density) Tim Raymund COO g5o~ West Hwy zq Georgetown, TX 786z8 ~ ~ T'hone. ~i2-zsq-bog5 ~,J Gells Siz-79t- 5557 K'~~'4~~~S.t15 ~ ~ax.~~~z-z;9-6oo-t ~x,~_~ ~ ~ i ~ ~ ~ ~ . . ~ ~ tiiT1~,Y8~IY1tifl.Cl~~S.iiS :.. : ~ z ~ I ~ ENGINEEItING AiVD DESIG3V i~i .. ~