Summary of sate of Minnesota water quality guidelines for stormwater harvesting and reuse systems for Irrigation

Summary of State of Minnesota water quality guidelines for stormwater harvesting and reuse systems for Irrigation
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Water Quality Parameter	Impact of Parameter 10	Water Quality Guideline – Public Access Areas	Water Quality Guideline – Restricted Access Areas	Water Quality Guideline – Irrigation of Food Crops	Comments
E. coli	Public Health	126 E. coli/100mL	Guidance to be determined at a future date	Guidance to be determined at a future date	2,3
Turbidity	Irrigation System Function	2-3 NTU	Guidance to be determined at a future date	Guidance to be determined at a future date	4,5
TSS	Irrigation System Function	5 mg/L	Guidance to be determined at a future date	Guidance to be determined at a future date	4,5,6
pH	Plant Health	6-9	Guidance to be determined at a future date	Guidance to be determined at a future date	4
Chloride	Plant Health; Corrosion of Metals	500 mg/L	Guidance to be determined at a future date	Guidance to be determined at a future date	7
Zinc	Plant Health	2 mg/L (longterm use); 10 mg/L (shortterm use)	Guidance to be determined at a future date	Guidance to be determined at a future date	8
Copper	Plant Health	0.2 mg/L (longterm use); 5 mg/L (shortterm use)	Guidance to be determined at a future date	Guidance to be determined at a future date	8
Temperature	Public Health	Guidance to be determined at a future date	Guidance to be determined at a future date	Guidance to be determined at a future date	9

² – MPCA Bacterial Impairment Standard: 126 E. coli/100mL (geometric mean of 5 samples in 30 day period); no individual samples greater than 1260 E. coli/100mL
³ – EPA 2012 Recreational Water Quality Criteria – Recommendation 1 (Estimated illness rate = 36/1000)
⁴ – Based on typical range/value for water reuse programs in other states
⁵ –Useful for distribution system design, but often used a general indicator parameter, too.
⁶ – TSS guidance provided by Cathy Tran, DLI
⁷ – Per Table R.3b.6 in Metropolitan Council Stormwater Reuse Guide
⁸ – Suggested by Bruce Wilson. Per Table R.3b.5 in Metropolitan Council Stormwater Reuse Guide
⁹ - Recommendation from Anita Anderson on 12/6/2012 email as temperature impacts bacterial growth
¹⁰ –Per Tables R.1a.1 and R.3b.5 in Metropolitan Council Stormwater Reuse Guide