The mean annual flow for this same period was 58.5 gallons per second. The highest instantaneous flow rates are usually in the winter. On 27 February 1979, for instance, the maximum instantaneous flow rate recorded was 3124 gallons per second. Flow rates in water wells vary from a few gallons per minute up to the seventy-five gallons per minute in a well at the Lady's Slipper Mushroom Plant in Lower Freetown . The groundwater chemistry is variable but tends to be a calcium bicarbonate water as shown on the results of a sample collected from the home of Mrs. Ralph R. Burns . Calcium = 73.0 mg/1 Magnesium = 2.35 mg/1 Sodium = 15.8 mg/1 Potassium = 0.92 mg/1 Chloride = 23.0 mg/1 Sulphate = 8.0 mg/1 Total Alkalinity = 147.0 mg/1 Labratory pH = 7.8 mg/1 Manganese = less than 0.02 mg/1 Dissolved iron = less than 0.1 mg/1 Extractable iron = less than 0.1 mg/1 Phosphorous = 0.12 mg/1 Nitrates as N = 4.2 mg/1 Zinc = 0.77 mg/1 Copper = 0.04 mg/1 Total Hardness = 183.0 mg/1 North Brook (back of Lewis' farm).