HomeMy WebLinkAboutItem 03 - Trinity River Authority ���i� � .��..__�
`� MEMO TO: HONORABLE MAYOR AND MEMBERS OF THE CITY COUNCIL
2
FROM: BRUNO RUMBELOW, CITY MANAGER �
MEETING DATE: JUNE 3, 2008
SUBJECT: TRA INTERLOCAL AGREEMENT — LAKE GRAPEVINE
DISSOLVED OXYGEN TRANSITION ZONE STUDY
RECOMMENDATION:
City Council consider approving an Interlocal Agreement (ILA) with the Trinity River
Authority (TRA) for the City's participation in a joint sampling study of the Dissolved
Oxygen Transition Zone in Lake Grapevine in an amount of $90,095, authorize the City
Manager to execute said ILA, and take any necessary action.
FUNDING:
Funds are currently programmed in the Water PCMF account 200-43360-534-0.
BACKGROUND:
Both the City of Grapevine and TRA were issued variances by the Texas Commission
on Environmental Quality (TCEQ) for their Texas Pollutant Discharge Elimination
System (TPDES) permits to discharge effluent from their separate wastewater treatment
plants into Lake Grapevine. The variances were granted to allow Grapevine and TRA to
conduct a lake study that determines actuai dissolved oxygen and other water quality
parameters in Lake Grapevine. The results of the study will be utilized by TCEQ to
calibrate the water quality model utilized to determine wastewater treatment plant
discharge limits.
TCEQ utilized an un-calibrated model to develop draft wastewater treatment effluent
limits that for the Grapevine wastewater treatment plant permit renewal were so
restrictive that plant modifications would have been required. Staff requested a permit
variance from the TCEQ that allowed for a three year period in which to conduct a lake
study to determine the actual lake conditions.
TRA has experienced a similar situation with their renewal effort and has agreed to
partner with Grapevine to conduct the study and share the cost.
TRA has previously hired the firm of Alan Plummer Associates, Inc. to prepare a
dissolved oxygen transition zone study work plan encompassing both TRA's and the
City's needs and submitted it to TCEQ under the current permit. This work plan was
R:WGENDA\06-03-08\TRA Interlocal Agreement-Grapevine Lake Study.doc
approved in late March of this year. This first phase of the overall study was funded by a
grant from the Clean Rivers Program. Both studies require significant sampling on the
lake over a two year period.
The ILA provides a means for the two entities to join in a single sampling contract for the
two year period with Grapevine's cost at $90,095 and TRA's cost at $177,395.
The City has previously hired Freese & Nichols, Inc. to prepare our permit renewal
application and subsequently has extended their contract to prepare a final report
submittal to TCEQ based upon the study results.
Staff recommends approval.
R:�AGENDA\06-03-08\TRA Interlocal Agreement-Grapevine Lake Study.doc
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