David Seitzinger, a Kingwood professional engineer, has studied Harvey flooding since it happened. In this letter to the SJRA Board, Seitzinger urges the SJRA to continue its seasonal lake lowering strategy until other flood mitigation measures can be implemented. Here, Seitzinger addresses one of the main causes of misunderstanding about the policy. Many Lake Conroe residents believe the lake will be lowered 1 or 2 feet from its current level (whatever that may be). However, the policy states the lake will NOT be lower below 200 or 199 from its normal target of 201. The SJRA has NOT lowered the lake since last October. Seitzinger shows that evaporation and below-normal rainfalls have taken the lake lower and kept it down, not the SJRA.
Text of Seitzinger Letter
San Jacinto River Authority
P.O. Box 329
Conroe, Texas 77305
Re: Lake Level Vote
Dear Board Members,
My message to the Board is to renew and maintain the terms of the SJRA/COH Temporary Flood Mitigation Strategy for Lake Houston and Lake Conroe for 2020.
The agreement is contingent upon the dredging operation in Lake Houston. Unfortunately, the “stream mouth bar”, the most significant river obstacle, has not been removed due to FEMA and Army Corps of Engineers limits that were applied to the first dredging contract, not agreed to by the City of Houston. A new dredging contract and associated funding were released, but contractor mobilization is just starting. This is expected to delay the complete removal by at least one year.
Impact of Drought
I have read about the complaints of the Montgomery County citizens at the recent Board meeting. I think that the lowering of the level as required by the contract is not the real problem. The real problem is the “moderate drought” conditions in the Lake Conroe watershed limiting the ability to refill the lake that successfully occurred in 2018. If we look at Huntsville for watershed drought conditions, its 2019 rainfall is 13″ behind normal. Conroe, on the other hand, is 8″ ahead of normal due to the effects of Imelda that were limited to East Texas.
Watershed drought conditions are not rare occurrences. Looking back over the past 20 years, two other drought periods (2001 and 2011-14) have created low lake levels well below the current level of 199 feet. There was also a period in 2005-06, where the lake level was reduced to 197 feet for six months to repair dam damage due to Rita. I am not sure how many bulkheads were replaced and if property values dropped as a result of those lake level conditions.
Steps Being Taken to Mitigate Flooding
City of Houston and Harris County are taking rapid steps to remove flood-causing obstacles in the West Fork of the San Jacinto River that will reduce flooding risk in the Kingwood/Humble/Atascocita area.
- HCFCD and SJRA are leading a comprehensive study of the San Jacinta watershed to model flooding conditions and identify mitigation strategies, which are expected to look at Lake Conroe water releases.
- COH completion of the “stream mouth bar” dredging at the juncture of the West Fork and Lake Houston.
- COH and CWA design and construction of additional gales at Lake Houston.
I have attached reference materials below for the history of water levels at Lake Conroe to support my lake levels and rainfall statements.
Lake Conroe Operation Requirements and Compliance for 2018 to 2020 To-Date
- Lake level requirements by “SJRA/COH Temporary Flood Mitigation Strategy”
- Lake level 2018 with complete compliance
- Lake level 2019 in compliance until October 2019. Lake level is not able to recover due to low rain fall in the lake watershed. Rainfall at Huntsville is is 13 inches below normal and classified as a Moderate Drought conditions. Conroe is ahead of annual by 8 inches due to Imelda in September. Imelda rain did not fall in Lake Conroe’s watershed.
Lake Conroe Last 20 Years of Lake Levels Highlighting Low Level Periods
Rainfall 2019 History Below the Dam
Lake Conroe Water Levels
Historical Variation in Reservoir Storage
Actual Specific Historical Lake Levels
Reservoir Description by USGS
Water level at Lake Conroe has been generally stable with a typical 1- to 2-foot drop in water level during the summer. The exceptions have been in 2001 when drought conditions caused summer water level to fall 3 feet below pool and in 2005-20-06 when damage to the dam caused by Hurricane Rita required the water level to be held at 4 feet below pool for about six months.
Posted by Bob Rehak on 1/31/2020
855 Days after Hurricane Harvey