At 3:30 PM, site RP Jose called to report the discharge of turbid water into the Ann Morrison Park waterway that runs along the bottom of the Bench and into the duck pond, and eventually the Boise River by the Crab Shack/Riverside Inn.

The cause of the discharge was related to trench work for the site by United Water and a need to increase the depth of groundwater and increase amount of dewatering.

UW utilized McAlvain's existing dewatering system which had been effectively treating the discharge to low turbidity levels with 1 pump running. For this operation 3 pumps were used simultaneosly and the increased flow rate created a whirlpool in the settling pond and disturbed silts & sediment within the pond. The 3 outlet hoses into the pond did not have proper dissipation BMPs installed and amount of water flushed this turbid water downstream, overwhelming the already in place wattles and check dams and vegetation that has grown in the creek bed. It sounds like this may have been occuring for several hours before the problem was noticed. I could see the settling pond water was brown but the groundwater fwas very clear.

Corrective action taken:
1. McAlvain shut down from 3 pumps to 2 pumps before my arrival, installed rip rap and pans at the hose outlets, and staked down a GatorGuard wattle at the outlet end of the pond to increase settling time/filter the water.
2. After seeing the outflow of turbid water from site was continuing, I requested they shut down to one pump since, which they did promptly.
3. Jose took a turbidity reading around 4:35 and it was at 94 NTU, which excedes the CGP limit.
4. All pumps were shut down at that time to allow settling in the pond and stop the flow of water out of the site.

After leaving the site, I found that the turbid water had filled the creek up to behind the Ann Morrison tennis courts with turbid water. The water seems to blocked in some sort of dammed up pool behind a gated area. I did not see a flume of turbid water entering or exiting the duck pond (which is the outlet to the river).

Will return to site first thing in the morning to check situation.

rescheduled for 11/6

No construction. No activity on BLD permit in over 10 months. No ESC issues at site. Site vegetated with cheat grass and weeds.

Site perimeter BMPs and construction entrance are installed and permits are onsite in the office trailer. There is no water in the drainage/irrigation ditch that is adjacent to site.

Recent utility work on the shoulder and the road have left a significant amount of loose dirt. No MS4 structures and it is not tracking out to Victory.

Correction notice issued to Kevin to sweep Beverly once utility is fully complete and road is patched.

Involta data center parking lot and drive has been paved for some time. No trackout or areas where sediment is leaving site. A landscaped berm has been installed as well as some trees. Work on the data center is in progress, most interior. No ESC violations observed. Approved.

Student project house is still in progress. Frame up and siding is being put on. No trackout from vehicles or sediment leaving. Very clean. Permit posted on job trailer. Approved.

Mill District Square is in compliance after the weekend rain event. No trackout or significant sediment runoff from vacant lots. Perimeter wattles are installed in certain areas. Washout is lined with remain capacity and not intermingling with stormwater runoff. DI bags are installed and do not need maintenance at this time.

Approved.

Permit posted. No sediment or trackout from site onto Paso Fino. Gator guard wattles installed at bottom of hill have captured a lot of mud and sand and prevented blowout to next site.

1 correction:

Need to perform maintenance on the wattles by removing the collected and restaking the wattles.

Notified RP/GC via telephone regarding the correction

Permit finaled. See DOC-finaled activity notes.

WIP, home near completion. Adjacent lot used for staging has been cleaned. Downslope wire backed silt fence is installed well and has effectively contained sediment. Permit is posted. No corrections required.

BLD still open but the exterior is completely stabilized and landscaped. No stockpiles of dirt or other materials. No further ESC inspections required, permit finaled.

Home is complete. All permit finaled. Yard is landscaped and all construction materials & loose sediment removed. ESC permit finaled.

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