City of Lawrence
David L. Corliss – City Manager
Cynthia Wagner - Assistant City Manager
Diane Stoddard - Assistant City Manager
Philip Ciesielski – Assistant Utilities Director
Dave Wagner – Director of Utilities
Mike Lawless – Assistant Utilities Director
Beth Frailey Krishtalka – Assistant to Director
Mark Hegeman – Utilities Operations Superintendent
Dave King – Utilities Maintenance Superintendent
January 18, 2012
Agenda Item – Authorize the City Manager to Execute an Engineering Services Agreement for Project UT1102KA Kaw WTP Raw Water Intake
Please include the following item on the City Commission Agenda for consideration at the January 24, 2012 meeting:
The project will provide for an evaluation of raw water intake and pumping strategies for the Kaw WTP resulting in a recommendation and construction documents for an additional raw water intake facility. The project will also include an assessment of the existing facilities and recommendations for modifications to mitigate current sand and future zebra mussel impacts. Analysis will include appropriateness of intake location(s), possible raw water supply locations, possible river dredging options, and other appropriate options. See the attached map for location reference.
The Kaw Water Treatment Plant treats water from the Kansas River to supply potable water to the City. The point of diversion (intake) is through a structure called a crib and is located in the river about 60 feet from the riverbank. There are currently three cribs in the river but only one is functional (attached photo). The history, as best can be pieced together, of the diversion points for the Kaw Water Treatment Plant is as follows
1. 1886 – A wooden crib was constructed. It was destroyed in or around 1927.
2. 1927 – A concrete crib was constructed to replace the wooden crib. This is the middle of the three cribs visible in the river. This structure is no longer in service due to the washout of the piping which was laid above the river bed.
3. 1954 – A steel crib was constructed. It is unclear if this was constructed as a redundant intake structure or to replace the loss of the 1927 structure. This is also visible in the river and is the eastern of the three. This structure is no longer in service due to the washout of the piping which was laid above the river bed.
4. 1974 – The currently active crib, the structure closest to the west river bank, was constructed in response to the loss of the 1954 structure and is visible in the river. The piping for this structure is constructed below the river bed and is encased in concrete.
Using the chronology above the average service life of the failed cribs was 29.3 years with the longest being in service for 41 years. The current structure has been in service for 37 years. In the event of a failure of this crib or its piping, the Kaw Water Treatment Plant’s capacity would be limited to the amount of raw water received out of the existing well field and temporary intake pumps placed in the river. The Clinton Water Treatment Plant, while recently expanded, does not have the capacity to provide treated water for the entire city, and wholesale customers during peak summer demands.
Twice during the Summer of 2011 the existing Kaw Water Treatment Plant intake lost the ability to draw water from the river. In each of these cases aggressive backflushing eventually restored service. However significant amounts of sand continued to be transported from the Intake to Low Service Pump Station 2. The transport and accumulation of sand and debris into Low Service Pump Station 2 eventually led to the failure of the traveling debris screen and the shutdown of both structures. Emergency cleanout of both structures and repairs to the traveling debris screen in Low Service Pump Station 2 were completed during July and August of 2011.
In 2007, as recommended in the 2003 Water Master Plan, Burns & McDonnell completed a study of the Kaw Water Treatment Plant raw water supply and low service pumping facilities. The recommended capacity improvements to replace the raw water pumps at Low Service Pump Station 2 were completed in April 2008. The report provided an evaluation of raw water supply options and associated budgetary project costs. The options included new surface water intake with an additional low service pump station, and a collector well field. The 2007 project cost estimates ranged from $8.0 to $22.0 million. The 2012 CIP Budget amount for the project is $7.15 million and is based on a scope including the currently proposed study and the construction cost of a surface water intake connected to the existing raw water pump station. Actual project construction costs will be updated based on the recommendations of the current study.
On August 9, 2011 the City Commission authorized staff to advertise a Request for Proposals for engineering services related to the project.
On September 9, 2011 proposals were received from two firms; Burns & McDonnell and Black & Veatch.
On October 4, 2011 the City Commission authorized staff to negotiate an engineering service agreement with the highest ranked respondent Black & Veatch.
On October 19, 2011 Department of Utilities Staff met with representatives from Black & Veatch to review the existing intake and river conditions and establish a scope of work for this phase of the project.
Department of Utilities Staff have negotiated an appropriate scope and fee for this phase of the project. Staff have worked extensively with representatives of Black & Veatch to establish the appropriate number of options to be evaluated and level of detail to be included in the study phase.
The recently adopted Design Fee Guidelines do not cover services related to Pre-design Studies. A review of water and wastewater facility related Pre-design Studies completed over the last 9 years shows these services have averaged 2.15% of the project’s estimated construction. The percentage has ranged from 0.46% to 4.27% depending on the complexity of the project and number of alternatives evaluated. The proposed fee on a percentage of construction cost basis is 3.1% or 1.1% depending on whether the fee is compared to the $8.0 million estimate for a river intake or $22.0 million for a collector well.
A detailed outline of the scope tasks and alternatives to be evaluated is presented below.
To complete this scope of work Black & Veatch have teamed with the following sub consultants:
Existing Intake System Evaluation and River Analysis
Existing Intake Evaluation
Investigate modifications to the existing intake which provide significant benefit in terms of operational reliability. This will include modifications to the existing intake as well as the pumping stations and pipelines that convey the raw water to the treatment plant. The evaluation will include an assessment of the physical condition of the infrastructure and its long-term economic life. The evaluation of the existing intake will be limited to two alternative configurations for consideration. In addition, the benefits and costs of bi-annual dredging operations to control the sediment at the intake will be considered.
Kansas River Channel Assessment
Review past reports, geologic info, historic aerial photos of river, proposed changes at the Bowersock Dam, and recent changes at the upstream bridge crossing to define the existing conditions and identify recent changes that may influence sediment accumulation. Historic rates of channel change will be used to predict the expected incremental changes in the bank location and may delineate areas where active erosion/deposition is expected.
Conduct a bathymetric survey to obtain the contours of the river channel below the water surface at 100 foot intervals from 1000 feet upstream of the KTA I-70 bridges to the Bowersock Dam (approximately 6000 lineal feet of river) and extending from top of bank to top of bank. Bathymetric survey will be supplemented with ground surveying to identify sand bar, shallow areas, and edges of the river bank. Existing LIDAR and contour data from the City’s GIS system for areas outside the river channel will be incorporated reducing the overall ground survey effort.
Develop and Analyze 2D Sediment Model
Develop a 2D computational model to assess flow patterns in the general vicinity of the Kaw WTP Intake Site. The model will extend from 1000 feet upstream of the KTA (I-70) bridges to the Bowersock Dam (approximately 6000 lineal feet of river). The model will be developed based on bathymetric survey and design data provided during the geomorphologic assessment and calibrated to known water surface profiles, discharge records, and available velocity data.
Once calibrated, the model will be used to evaluate the potential for sediment deposition as a result of the recent changes to the bed and channel protection near the bridge. The hydraulic model will be run for four flow rates ranging from the 10% exceedance flow, the mean annual peak flow, the 5-year peak flow, and the 100-year peak flow. The model will be run for existing conditions and two alternative configurations which will include some type of submerged or emergent dike structures to alleviate any adverse sediment deposition in the vicinity of the improved intake.
Perform Scour and Sedimentation Analysis
This task will involve the review and analysis of information from the above tasks to determine the project impacts on local scour, erosion, and deposition. The modeling results will be used to identify locations where hydraulic shear may be affected by the project. Knowledge of the ambient hydrodynamic conditions will provide an understanding of the impacts of changes in flow induced shear stresses and identify areas which may become prone to erosion or deposition. The projection of the intake structure into the channel is also likely to induce local scour.
Conceptual Supply Option Evaluation
The short list of conceptual supply options identified at the project kickoff meeting will be further developed to establish preliminary cost estimates, operational and maintenance cost, and to develop a listing of advantages and disadvantages. Present worth costing will be performed for comparison of the supply options with cost adjustments for future construction cost (i.e. other plant improvements). The scope and associated fee for this phase is based upon evaluation of the following supply options.
Evaluate locations for new intakes including a bank intake, t-screen intake in the river channel, and crib intake in the river channel. Two (2) bank and two (2) channel locations will be evaluated.
Review previous studies and other available hydrogeologic information. Based on the review estimate the capacity and costs of up to three (3) collector well fields along the Kansas River.
Water Treatment Impacts
Review available water quality data from the Kansas River, groundwater and the Water Master Plan recommendations. Potential impacts to treatment processes and plant operations will be evaluated. Algal toxins and zebra mussels will be considered to the degree necessary for development of conceptual capital associated with each.
Develop Report and Conduct Project Review Meeting
A report documenting and comparing the supply options will be developed submitted to the City for review. Upon review by the City, a progress meeting will be held at the Kaw Water Treatment Plant to discuss the results and establish the preferred alternative for implementation. Comments from the meeting will incorporated and a final report issued.
Project Funding: The project is included in the Department of Utilities 2012 Rate Plan and Capital Improvement Program.
Action Request: Authorize the City Manager to Execute an Engineering Services Agreement with Black & Veatch in the amount of $246,354.00 for a Pre-design Study for Project UT1102KA Kaw WTP Raw Water Intake.
Thank you for your assistance. Please advise if you have any questions.