The following is a "cut-and-paste" from my 26 May 2024 article in the Killeen Daily Herald...





On Thursday afternoon, 23 May, the Union Grove boat ramp within Union Grove Park on the south shore of Stillhouse Hollow Lake was closed to the public and will likely remain closed for at least a month due to still-rising flood waters from the Lampasas River watershed.

That was the last remaining public ramp open on Stillhouse. Belton Lake’s public ramps were all already closed, as well.

I try to keep my finger on the pulse of our Central Texas fishing community, and lately I have seen a few questions raised about whether the pipeline connecting Stillhouse Hollow to Lake Georgetown could be used to both reduce the lake level at Stillhouse, while at the same time helping fill Lake Georgetown, which is currently approximately three feet low.

For those familiar with Stillhouse Hollow, there are two obvious structures at the lower end of the lake. One is centered along the face of the dam — that controls the flow of water though the dam.

The other is located just inside the mouth of the easternmost cove on the lake’s south side. It is the latter which pumps water into the pipeline headed for Lake Georgetown.

As we seemed stuck in drought conditions only a short time ago, some blamed Stillhouse Hollow’s low levels on the amount of water being taken out of Stillhouse and sent to Lake Georgetown.

To get to the bottom of all of this, I reached out to Brad Brunett, the Central and Lower Basin Manager for the Brazos River Authority.

Here are my questions and his answers:

How is the pipeline connection Stillhouse Hollow Reservoir to Lake Georgetown properly referred to?

Brunett: The Brazos River Authority refers to it as the Williamson County Regional Raw Water Line (WCRRWL).

Who manages this operation?

Brunett: The Brazos River Authority manages operation of the WCRRWL.

How long has this been in operation?

Brunett: It has been operational for about 20 years. The first transfer of water occurred in 2006.

What are the authorized parameters under which water may be transferred?

Brunett: Water is transferred based on “trigger level” water elevations at Lake Georgetown. The “on” trigger level is currently set at elevation 783 feet above mean sea level (ft msl), which is eight feet below normal pool elevation, and the “off” trigger level is set at 785 ft msl, which is six feet below normal pool elevation. So, when Lake Georgetown drops below elevation 783 ft msl, we begin pumping, and when it rises above elevation 785, we stop pumping.

The trigger levels are reviewed annually and are established to ensure that enough water is pumped to maintain water supply through an extended drought for the customers that rely on Lake Georgetown for their water, while at the same time minimizing the potential for pumping so much water that it gets spilled (or released) during the next flood event. We do not attempt to keep Lake Georgetown full by pumping water from Stillhouse Hollow.

It requires a lot of electricity to pump the water, so we try to be as efficient as we can and only pump what’s needed for reliable water supply. Last August alone, the WCRRWL electricity bill for the month was over $400,000. The three customers that rely on the pipeline pay 100 percent of the costs.

What is the pipe’s diameter?

Brunett: 48 inches

What is the pipeline’s maximum carrying rate?

Brunett: With the current pump configuration, we can transfer about 65 cubic feet per second. At this pumping rate, it takes about 50 days to lower the Stillhouse Hollow Lake elevation by one foot when it is near full. At final build-out, which is expected occur by about 2028, pumping capacity will increase to about 86 cubic feet per second.

What is the primary purpose of the pipeline?

Brunett: To provide a reliable drinking water supply for the BRA customers that depend on Lake Georgetown.

In a flooding scenario as we have currently, can extra water be sent to lower Stillhouse when Georgetown is below full pool?

Brunett: Yes, it could; however, as indicated in some of the answers above, there are a number of factors to be considered. Currently, Lake Georgetown is less than three feet from being full and is still rising. The weather outlook for the next few weeks appears to be wetter than normal, so it is likely that Lake Georgetown will fill up on its own from rainfall and runoff. It would be wasteful and inefficient to be pumping in this situation when it’s likely not necessary, only to have the water be released downstream from Lake Georgetown when it fills up. Also, Stillhouse Hollow Lake is currently 14 feet above normal pool and rising. It would take over 50 days of pumping to lower it one foot.

It appears that the water from Stillhouse boils up from the bottom of Georgetown instead of pouring in from above the lake’s surface. Is that true, and, if so, why that design?

Brunett: Yes, the discharge at Lake Georgetown is under the water surface. This is for public safety and water quality considerations. The water is pumped at depth from Stillhouse Hollow Lake and discharged at depth in Lake Georgetown.

You made clear the “bracket” for sending water to Georgetown where Lake Georgetown’s elevation is concerned, but what about similar requirements at Stillhouse?

We don’t have any trigger levels for Stillhouse Hollow. Currently, we are able to maintain water supply at Lake Stillhouse Hollow through all pumping scenarios without needing any trigger levels, and the Belhouse Drought Preparedness Project (the connection of Lake Belton to Lake Stillhouse Hollow) will help us continue to do that into the future as the region grows.

Excellent Report....

Thank you Bob.

Good info!

You ever run any trips on Lake Georgetown? All ramps open. Lake level only down 2.75 ft.

I do. Here's a report from such a trip I conducted there just this week: Georgetown Report