Last week we covered dredging Hulah Lake and other options that have and have not been pursued by the City (and why) to ensure adequate water supply into the future. Back for Part 2 of your most Frequently Asked Water Questions, Water Utilities Director Terry Lauritsen talks feasibility and costs in today’s Director’s Cut.
First, remind us of the options that have been explored and identified since the drought in 2001-02 that got everyone’s attention.
A study was completed in 2008 that looked at the following:
- Accessing water at Kaw Lake
- Accessing water at Copan Lake
- Reallocating flood control to water supply at Hulah and Copan lakes
- Building Sand Lake
- Dredging Hulah Lake
It was determined the most cost effective option was to purchase the remaining water storage rights at Copan Lake and reallocate five percent of the flood control at Hulah and Copan to water storage. The study also looked at accessing water at other regional lakes, including Birch and Oologah, but these lakes either didn’t have any water rights available or not a significant amount of rights to warrant further investigation.
What actions were taken as a result of the study?
As a result of these findings and information that has come to light since, in 2020, the City purchased the remaining storage rights at Copan Lake — 2,500 acre feet, or 1 million gallons a day — which took a federal act of Congress and more than 12 years of work through the legislative process to keep the cost affordable for our customers.
The City is also implementing water reuse, which takes treated wastewater and pumps it upstream of the City’s raw water intake on the Caney River, where we can recapture and send it to the water plant for further treatment.
Reallocation of Copan and Hulah will be pursued in the future, but reuse was prioritized over reallocation because water reuse is not impacted by drought or other environmental factors that can affect water availability at Hulah or Copan lakes. Water reuse was first authorized by the state legislature in 2012, thus it was not even possible when the initial study for long term water supply was completed in 2008.
One of the most often asked questions we get is why we don’t dredge Hulah Lake. Can you remind everyone of why that is?
Dredging Hulah Lake doesn’t make sense simply from a cost versus Return on Investment basis. The cost to dredge the lake would easily be in the $150 million-range, and that’s a low estimate. Other factors include a long permitting process and complications in disposing of the organic material. Silting would then reoccur over time, making this option less long term than desired.
Why can’t we build a new lake?
In the 2008 study looking at water supply options, the estimated cost to construct Sand Lake was $86 million, which is likely around $120 million today. This estimate does not include costs for the acquisition of mineral rights and impacts to environmental and cultural resources, which are likely significant. The water we could get from Sand Lake was estimated at 12 mgd and would meet projected demand for the next 50 years. However, the costs, time and uncertainties securing mineral rights, environmental and cultural impacts makes this option less desirable compared to other options available to the City.
Why can’t we get water from Kaw Lake?
In the 2008 study looking at water supply options, the estimated cost to secure water rights at Kaw Lake and construct a pipeline was $106 million, which is likely around $150 million today. This estimate does not include costs for the mitigation of environmental and cultural resources impacts.
Can you break the feasibility of these options versus costs down to a manageable level?
Sure. Here is a summary of the options available, the estimated costs and amount of water we can secure. (Keep in mind our projected average demand in 2065 is 8.2 mgd, and Hulah’s estimated yield in 2065 is 4 mgd.)
Water Reuse
$10 million for 4.1 mgd
Reallocate 5 percent of Hulah and Copan flood pool to water supply (includes a pipeline from Copan to Bartlesville)
$85 million for 16 mgd
Build Sand Lake
$120 million for 12 mgd
Access Kaw Lake (includes pipeline)
$150 million for 14 mgd
Dredge Hulah Lake
$150 million. This would recapture 8 mgd lost to sedimentation
Secure available water storage at Copan Lake:
$7 million for 1 mgd (through legislative efforts, this cost was reduced to $250,000)
To break it down, the most cost effective measures we can take to ensure we can meet our water needs into the future are to combine water reuse and reallocation at Hulah and Copan lakes. These measures combined would result in a yield of more than 20 mgd for a total cost of about $95 million, compared to more expensive options for less yield.
The City started investigating the feasibility of water reuse in 2016. Detailed studies completed in 2017 and 2018 confirmed its feasibility and treatment, along with environmental impacts. The City was able to take advantage of stimulus funded grants through the Bureau of Reclamation ($900,000) to construct the conveyance system (pump station and pipeline), which is anticipated to be complete mid-summer 2023. The regulatory approval process will take longer, but it will happen, and water reuse will be one of the most effective steps we can take toward meeting increased demand in the future.
How is the overall water supply measured?
For the lakes (Hulah, Copan and Hudson), we measure the volume of water (acre feet) above the inactive pool compared to the volume of water at the top of the conservation pool. Storage from flood control is not considered in the calculation. The inactive pool is the lowest elevation where water can be released through the dam (Hulah and Copan) or pulled through our intake structure within the lake (Hudson). For the City to access water at Hulah and Copan, the Corp of Engineers has to release it through the dam. The conservation pool is the normal level of water maintained at the lake.
On Hulah and Copan, this information is from the COE websites (https://www.swt-wc.usace.army.mil/HULA.lakepage.html, https://www.swt-wc.usace.army.mil/COPA.lakepage.html). For Hudson Lake, we read this manually from a gage on the intake structure.
We also pull water from the Caney River. The percent remaining on the Caney is based on how much water the COE is releasing from Hulah and Copan. The COE is required to release at least 10 million gallons per day combined from Hulah and Copan to maintain aquatic life in the river. We can remove 6 million gallons per day from the river based on our water right. Thus, if the COE is releasing at least 6 million gallons per day, then we have 100 percent capacity at the Caney River.
The overall percentage of water remaining is the aggregate total of the water available at all the lakes and through the Caney River.
For more information about Bartlesville area water supply, usage, and water system history, see www.cityofbartlesville.org.