Chemical and Physical Properties of Connecticut Lakes, With Emphasis on Regional Geology

ABSTRACT

Chemical and physical characteristics of 60 drainage lakes in Connecticut are discussed in relation to the geology of the state. Significant differences in composition and quantities of dissolved ions were observed for lakes in different geologic zones. Waterbodies situated on the Eastern Uplands, Western Uplands, and Coastal Slope were more dilute than lakes in the Marble and Central Valleys. Although there were significant differences in Na⁺, Ca⁺², Mg⁺², Cl⁻, SO₄ ⁻², and alkaline anions between different regions, none were found for K⁺. Unlike ionic chemistry, few differences in trophic variables were observed for lakes in the different geologic areas. On a statewide basis chlorophyll a levels were highly correlated with total phosphorus (TP), total nitrogen (TN), and Secchi disk depths. Summer TN:TP ratios suggested that chlorophyll levels in many lakes may be related to both TP and TN levels. Results are compared to previous studies in Connecticut and other areas of the northeast.

Key Words:

• Connecticut
• dissolved salts
• alkalinity
• geology
• eutrophication
• New England