Plum Creek Conservation District

PLUM CREEKCONSERVATION
DISTRICTN E W S L E T T E R
V O L U M E

1N U M B E R

82 0 1 6

Halloween Flooding— 2015
INSIDE THISISSUE:Halloween Flooding2015
Page 1Site 6 Rehab Project
Page 2

As many of you are aware of, Texas’ climatic cycle of droughts and floods can be quite extreme. OnOctober 30, 2015, areas in Plum Creek Conservation District experienced flooding similar to flooding backtwo years ago in October of 2013. Several of PCCD’s dams had their auxiliary spillways activated,causing, in some cases, moderate to severe erosional damage. As with the 2013 flood, there was asignificant amount of debris washed in and around the structures. The dams that were affected by theflooding were sites 2,5,6,7,10,11,12 and 14. PCCD is currently in the process of applying for flood relieffunding. Back in 2013 PCCD received funding through a Federal Emergency Management Agency(FEMA) disaster assistance program; however, this time the necessary funds may be provided by theNatural Resources Conservation Service (NRCS) through its Emergency Watershed Protection (EWP)
program .
During any flooding event, PCCD monitors the integrity of each of its dams. If a dam becomes in dangerof failing, then PCCD would activate its Emergency Action Plan (EAP). Through the EAP, local
emergency personnel would evacuate certain areas, if necessary, and steps would be taken to secure thedam if possible.
Emergency
notification to landowners locatedin the flood inundation areas
would be done primarily throughtheReverse
911
system.
Residents in Caldwell and Hays
county can register their cellphones for the Reverse 911
service through CAPCOG CapitalArea Council of Governments’Regional Notification System at
http://wireless.capcog.org or call(866) 484-3264. All of PCCD’s“high hazard” dams require anEAP.

Water Levels
2015/2016
Page 2

GMA 10 & 13 DFC
UpdatePage 3

Division requirements call for a dam tobe able to withstand the Probable
Maximum Flood (PMF). The PMF is themaximum runoff condition resulting fromthe most severe combination ofhydrological and metrological conditions
that are considered reasonably possible
to occur. To meet the PMF it would benecessary for PCCD
to rehabilitate
many of its dams.
Currently, Site 5 is the only dam that has
been rehabilitated up to TCEQ
standards, while Site 6’s rehabilitation
projectisunderway.
Preliminary
rehabilitation
plans
have
been
completed for four (4) “high hazard”
dams (Site 10, 12, 21,and 28) and now
await to see whether the necessary
federal and/or state funding becomes
available .

Site # 6 Flood Damage to Auxiliary Spillway

When originally built back in the1960s and 70s, many of our dams
were designed to withstand a 25year flood event. Now, the Texas
Commission on Environmental
Quality (TCEQ) —Dam Safety

Site # 6 Auxiliary Spillway Flood Release on 10-30-2015

Spring 2016 Water Levels
PAGE2The table below shows water levels for 11 wells that were measured in the Winter of 2015/2016 alongwith their corresponding lowest recorded water level. If you are interested in finding out the water level inyour well and how it compares to other wells in the area, contact us to schedule a time to measure yourwell. A complete listing of PCCD water levels can be found on our website at www.pccd.org
Well

Winter 2015/2016 Levels

Lowest Recorded Level

Kosarek- 47.25- 50.8

Larsen- 21.45- 22.8

Lipscomb- 90.05- 93.9Lockhart #8- 79.1- 108.0

McCormick #2- 66.45- 71.00

2015/2016

McCormick #1- 71.7- 71.75

Water Levels

Moore- 64.65- 70.6Nohra- 105.92- 130.67

Platt- 123.7- 123.7

Wells- 80.95- 90.35

Williams- 75.75- 83.05

Site 6 Rehab Project Update
Site 6 Rehab construction project is now in full swing and is currently about 25 % finished with expectationsof finishing in the Fall of 2017. The rehabilitation project is being performed by Archer Western. They havecurrently closed Goforth road that runs along the downstream area due to road realignment and safetyconcerns. The detour routes traffic using Cotton Gin Rd. and Shady Oaks Dr. Businesses in the area, such
as La Mexican, Perdue Auto Sales, and Un Dollar Y Mas, along with the North Hays Optimist Sports
Complex, have open access for their customers and the public.
One of the first construction objectives was thebuilding of the temporary coffer dam pictured to theleft. The purpose of the coffer dam is to provide
protection from flooding during the construction
phase. The triangle shaped coffer dam height isalmost equal the top of the dam.

Site 6 Rehab
Project Update

On May 27, after significant rains, the lake levelrose to approximately 4 ft. below the crest of thecoffer dam. With an additional 6-8 inches of rain
forecasted, Site 6’s EAP was initiated in order toplan for the possible overtopping of the coffer dam.
Plastic tarps were placed on the coffer dam toprevent erosion, a channel was excavated in theauxiliary spillway by Archer Wester to slow the rateof water level increase in the reservoir, and residencesimmediately downstream of the dam were put on alert for
further notification by the Hays County office of Emergency
Management. Fortunately, the forecasted rains did not occur
and since then the reservoir has drained to a safe level.
When finished, the new dam will contain approximately
994,000 pounds of steel and 6,933 cubic yards of concrete.
The new dam will be only one of 3 dams in the state ofTexas with a labyrinth weir type design.
The beginning stages of the dam’s stilling basin are being
constructed as pictured to the right. The stilling basin isbeing built in and under the present location of Goforth Rd.
Because of this, Goforth Road’s new location will be shifted
southward. More specialized fill and concrete will be laid
within the basin along with other added structuralcomponents of the dam before the stilling basin will becomplete.

PAGE

GMA 10 & 13 DFC Hearings
After meeting with Groundwater Conservation District representatives in Groundwater Management
Areas (GMA) 10 & 13, the PCCD has completed the process of proposing “Desired Future Conditions” (DFCs) for all relevant aquifers.
What are DFCs? DFCs are mandated by State law requiring Groundwater Management Areas (madeup of individual groundwater conservation districts) in Texas to propose and eventually adopt a DFC. ADFC is, in essence, a management goal that addresses how an aquifer should be managed. A DFC
answers the question- what do you want your aquifer/s to look like in the future? For example, a DFC
could be based on spring flow or, perhaps, on water levels. The process for determining DFCs, involve
running computer models (developed by the Texas Water Development Board) which simulate the effects of pumping from an aquifer. After running a model through several iterations of various pumping
from high to low, one will be able to see a range of impacts. GMAs must consider a number of things
when proposing a DFC which include (1) aquifer uses or conditions, (2) the water supply needs andwater management strategies included in the state water plan, (3) hydrological conditions, (4) other environmental impacts, including impacts on spring flow and other interactions between groundwater andsurface water, (5) the impact on subsidence, (6) socioeconomic impacts reasonably expected to occur,(7) the impact on the interests and rights in private property, (8) the feasibility of achieving the desired
future condition, and (9) any other information relevant to the specific desired future conditions . In addition, a DFC must provide a balance between the highest practicable production of water and the conservation, preservation, and protection of the aquifer.
Below are listed the proposed DFCs for GMA 10 & 13 that are directly related to our District .

GMAAquifers

Proposed DFC 2016

Proposed Date10Trinity GroupA regional average well drawdown during average
recharge conditions that does not exceed 25 feet(including exempt and non-exempt well use)

March 14, 2016

10Saline Edwards

No more than 75 feet of regional averagepotentiometric surface drawdown due to pumping
when compared to pre-development conditions.

March 14, 2016

The first proposed desired future condition for the CarrizoWilcox/Queen City/Sparta Aquifers in Groundwater
Management Area 13 is that 75 percent of the saturated
thickness in the outcrop at the end of 2012 remains in
2070. This desired future condition is considered feasible
despite model predictions to the contrary as detailed in
GMA 13 Technical Memorandum 16-08.

13Carrizo-Wilcox, etal

In addition, a secondary proposed desired future condition
for the Carrizo-Wilcox/Queen City/Sparta Aquifers in
Groundwater Management Area 13 is an averagedrawdown of 48 feet for all of GMA 13. The drawdown iscalculated from the end of 2012 conditions to the year
2070. This desired future condition is consistent with
Scenario 9 as detailed in GMA 13 Technical
Memorandum 16-01 and GMA 13 Technical
Memorandum 16-08.

April 27, 2016

PCCD has finished holding two hearings for the proposed “Desired Future Conditions”. GMA 10’s hearing was held on May the 17th and GMA 13’s DFC hearing was held on June the 21st. Comments , bothoral and written, will then be reviewed by the GMAs before a DFC is adopted. Once a DFC is adopted
by the GMA it is then sent for approval to each individual Groundwater Conservation District. Finally,
DFCs are then incorporated into a district’s management plan and rules.
Copies of the DFCs along with supporting documentation are available at www.pccd/News and Notification.com and at our office . June 30th was the deadline for submitting comments concerning GMA 10’s
DFC and August 1st , 2016, for GMA 13.

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