Once again, the topic of what to do with Cape’s Dam has come up. The City Council voted in 2016 to remove the dam with funding through USFWS. The topic became controversial and has been delayed in action ever since.
Hays County is bringing a conceptual Master Plan to the San Marcos City Council on Tuesday, October 15 at 3:00. The City must decide if they would like to collaborate on this project with the County. This will be a work session, so no public comment will be allowed, but we plan to attend and urge you to do the same. If 3:00 that day is not possible for you, we hope you can attend the council meeting that evening at 6:00. Turnout will be important so please come when you can!
What is the goal of the plan proposed by the Hays County Historical Commission? The vision presented “Seeks to promote the rehabilitation and interpretation of the Thompson/Cape dam, mill race, Thompson/Cape mill site and turbine structure, as a special place; the very beginning of San Marcos Industry.”
Here is the link to the conceptual Master Plan for your viewing:
We see many issues with the above concept and urge all citizens and elected officials to consider the following:
- SMRF’s main concerns regarding Cape’s Dam have always been the diversion of water into the mill race and the protection and expansion of the endangered species in the San Marcos River.
- The Edwards Aquifer Authority was established in 1993 and implemented in 1996 to ensure that the Edwards Aquifer contained enough water to keep both the Comal and San Marcos Springs flowing because of the presence of Endangered Aquatic Species. So essentially, these protected species ensure a flowing river for us all to enjoy.
- As Central Texas continues to increase in population, pressure and demand on the aquifer only continues to grow. Droughts occur more severely and frequently which also reduces spring flows. We shouldn’t be diverting part of the river as this gets worse. To read more about San Antonio Springs that stopped flowing after too much demand click here: Springs Dry Up
- The mill race diverts 1/3 of the water out of the river in times of normal flow. As the water drops (in times of drought) the percentage of the river being diverted actually goes UP. The mill race channel continues to widen with flood damage and erosion, diverting more water from the natural river channel. This is damaging to the ecology of the river channel. The dam promotes unnatural sediment build up upstream of the dam, increases water temperature and decreases dissolved oxygen, impedes upstream and downstream movement of aquatic animals, and decreases the rivers’ natural ability to transport sediment farther downstream.
- There is no Texas Wild Rice in the mill race. One of the types of aquatic vegetation that Fountain Darters live in is Texas Wild Rice. The 2018 EAHCP report shows that the goals for Texas Wild Rice have not been met below IH-35. The Wild Rice and Fountain Darters thrive in clear & flowing water with appropriate aquatic vegetation. See more here: Fountain Darters and EAHCP 2018 Annual Report
- The stagnant nature of the mill race around Thompson’s island slows the water down, creates a rise in temperature and makes it more prone to bacterial contamination. It then empties back into the river at the end of the mill race which is again, not good for the health of our river or recreation.
- The mill race is compromised by two clusters of seeps that will continue to erode and eventually completely blow out. There are several deep sink holes on the island that are caused by this effect. This makes the area less safe for residents and increases erosion and turbidity, in which the endangered species cannot thrive.
- The sediment built up behind the crumbling dam is also causing a loss of potential habitat.
- Flooding in this particular part of the river will continue. The more structures that are built in the area will mean more costly maintenance of those structures after floods. As we have seen in other parts of the river, including Rio Vista, while repairs are underway parks and public access will be closed. More details:Park Closures Due to Damage and Millrace footbridge collapse
- The cost to create, fix, and maintain a dam structure that is not serving its original purpose will be a financial burden to the citizens of San Marcos or Hays County or both… depending on ownership of the project. SMRF has a lot of questions about the ownership structure of such a plan. Will there be a transfer of land for which the citizens vote? Will there be an MOU? Will Hays pay for it and San Marcos manage it or vice versa?
- Since the San Marcos River is part of the Waters of the US, structures in the river will require the Army Corps of Engineers approval and permitting. Approval of this type of project would be questionable in light of scientific evidence regarding old dams.
- US Fish and Wildlife Service and Texas Parks and Wildlife Department have written formal letters of support for Cape’s dam removal. Because of the endangered species present in the river, the USFWS will require separate permitting for the rebuilding of such a dam. The environmental permitting alone can cost 10s to 100s of thousands of dollars. The process is also extremely time consuming and will prolong the closure of Thompson’s Island.
- Parking for this master plan is not fully addressed. How will this affect the neighborhoods adjacent to the project? Where will parking be located, how many spots will be allocated and what will the surface structure be? Our concern is increased impervious cover in a flood plain. Will there be other unintended consequences for the neighboring areas?
- Is Hays County only interested in partnering if the dam gets preserved/rebuilt? Most of the conceptual master plan could be discussed without rebuilding the dam.
SMRF recognizes that the dam and its structure which were built over a century ago have historical interest, but rebuilding a damaged and dangerous dam in light of what we now know about healthy rivers and habitats is fraught with ecological consequences and never-ending financial burden. The San Marcos River deserves to be free-flowing and the removal of the dam will enhance the area by returning the river to its natural hydrology and ensure its long-term health and that of its unique species. The river is a central part of our community and we firmly believe that the community would like to see us preserve and protect it in the best manner possible.
More information can be found on our website: San Marcos River Foundation