The Lake Conroe area has already experienced three to six inches of rainfall this week, and the latest forecast from the National Weather Service indicates that additional heavy rainfall is expected this afternoon.
As of 2:00 PM today, Lake Conroe is one foot over its “full” level of 201’ above mean sea level, and SJRA is currently releasing water from the dam at a rate of 6,978 cubic feet per second. Based on the combination of saturated ground conditions, high inflows into the reservoir, and the current forecast and lake level, it is likely that increases in the rate of release from the dam will be required.
We are working within our operational protocol to buffer releases to the extent we can. Safety is always our first concern – both the safety of the structure and the safety of residents upstream and downstream of the dam. Even though Lake Conroe is not designed as a flood control reservoir, it does buffer downstream impacts by holding some water behind the dam and releasing this water slowly over time.
Anyone living in low-lying or poorly-draining areas is encouraged to monitor local conditions and take any necessary precautions. The Montgomery County Office of Emergency Management maintains a list of road closures and other important information on its website at www.mctxoem.org.
There are a number of separate drainage basins (or watersheds) that contribute flow into the San Jacinto River. The Lake Creek watershed received over five inches of rainfall in the past 72 hours and is currently contributing approximately two-thirds of the river flow at IH-45. Releases from the Lake Conroe dam are not indicative of the flows that will occur in other drainage basins. Residents should monitor stream conditions in their area to determine if evacuation is necessary. See Figure 1 below for a map of local drainage basins.
SJRA provides continuous data regarding lake level and release rate on its homepage at www.sjra.net. In addition, historic data can be accessed by clicking the link labeled “Additional Data” (look for the map labeled San Jacinto Contrail Web). There are excellent resources on the Additional Data page that provide up-to-date information on rainfall, stream flows, lake level, and other important weather information.
SJRA personnel are currently conducting 24-hour operations and will continue to monitor the forecast and the rate of continued lake level rise to determine if and when additional increases in the release rate may be required.
Figure 1. This map shows the various drainage basins that contribute flow into the San Jacinto River and ultimately to Lake Houston.