Photo: Dave Jenkins, CPESC
The sample on the left is just under 1 NTU
, the middle is 25 NTUs, and the one on the right is 250 NTUs. In Washington state, the Construction Storm Water General NPDES Permit
lists benchmarks that construction discharges must meet. These are: 0-25 NTUs everything is cool; 26 -249 NTUs not so good, upgrade your site best management practices (BMPs
) and modify your SWPPP
; 250 NTUs and above, call the Dept. of Ecology
, upgrade BMPs, modify the SWPPP and monitor the water body that the project discharges to until you are in compliance.
#turbidity
#NTU