Presenter/Contact
Presenter
Irvine and Conner, PLLC, Protect Lake Dunlap Association, and Dr. Thom Hardy, Texas State University
Contact Info
Subject Header
SUBJECT:
Title
Presentation and possible direction to staff regarding the management of floating aquatic vegetation in the Comal River.
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BACKGROUND / RATIONALE:
Throughout recent years, the City has received intermittent complaints from the Protect Lake Dunlap Association (PLDA) and residents of Lake Dunlap regarding the accumulation of debris and floating aquatic vegetation within the lake. Most recently, the City was approached by Irvine and Connor law firm, who represents PLDA and residents of Lake Dunlap, to find a solution to reduce the accumulation of debris and floating vegetation in the lake.
Landa Lake and the Comal River naturally produces an abundance of submerged aquatic vegetation that proliferates due to the clarity of the water and stable, relatively warm water temperature. Aquatic plants in Landa Lake and the Comal River naturally shed fragments and these fragments float to the surface of Landa Lake/ Comal River. The floating aquatic vegetation tends to float downstream through the Comal River towards the Guadalupe River and into Lake Dunlap. As floating vegetative material moves downstream it can become entrained on tree limbs, structures, etc.
The City, as part of the federally-approved Edwards Aquifer Habitat Conservation Program (EAHCP), has an obligation to dislodge floating vegetation mats from portions of Landa Lake where it has the potential to negatively impact habitat of the endangered fountain darter. As such, the City receives funding through the EAHCP to manage floating vegetation and has contracted with Pristine Texas Rivers (PTR) to dislodge floating vegetation mats from Landa Lake on a weekly basis and allow them to float naturally downstream. After floating vegetation migrates downstream through the Mill Race of the Comal River it tends to accumulate in the Mill Pond which is formed by the old hydroelectric dams adjacent to Wurstfest. New Braunfels Utilities (NBU) opens the hydroelectric dam gates at regular intervals (approximately weekly) which allows floating vegetative material to continue floating through the Comal River towards the confluence with the Guadalupe River. There is minimal to no management of floating vegetative material by the City or its contractors downstream of the hydroelectric dam gates. Aside from requirements of the EAHCP to dislodge floating vegetation, there is no other regulatory requirement regarding management of naturally-occurring aquatic vegetation.
Irvine and Conner worked with Dr. Thom Hardy, a scientist with the Meadows Center for Water and the Environmental at Texas State University, to develop a plan to remove floating vegetation from the upper portions of the Comal River to attempt to reduce accumulations in Lake Dunlap. The initial plan involved utilizing funding through the EAHCP to remove floating vegetation from the Comal River. This plan was presented to the EAHCP Science Committee in November 2018. The EAHCP Science Committee stated that impacts of floating vegetative material in Lake Dunlap was outside the scope of the EAHCP. Furthermore, removal of floating vegetative material offers no apparent benefit to endangered species and therefore difficult to dedicate funding through the program to support this activity. No formal action was taken by the EAHCP Science Committee regarding this matter.
City staff has acquired quotes from three contractors to determine costs associated with removal of floating vegetation from the Comal River. While the removal of the floating vegetative material appears feasible, there remains some logistical questions and challenges. It is also unclear as to whether the City should be responsible for removal of naturally-occurring floating vegetative material and whether removal would significantly reduce accumulations of debris and floating materials in Lake Dunlap.
ADDRESSES A NEED/ISSUE IN A CITY PLAN OR COUNCIL PRIORITY:
FISCAL IMPACT:
There is no budget allocation in the City’s FY18/19 budget or in the City’s EAHCP budget to support removal of floating aquatic vegetation from the Comal River.
Recommendation
COMMITTEE RECOMMENDATION:
None
STAFF RECOMMENDATION:
None