AWWA SYM53628

Utilities with multiple raw water sources from diverse watersheds will requirecarefully designed source water management and treatment strategies to ensurecompliance with more stringent drinking water regulations. The City of Boulder,Colorado, treats surface water from multiple watersheds and experiences treatmentchallenges from source water natural organic matter (NOM) resulting indifficulties for both particulate removal and disinfection byproduct (DBP)mitigation. NOM studies were conducted to quantify and characterize NOM and toevaluate raw water potential for DBP formation by watershed and seasonality. Ten different tributaries within multiple watersheds were evaluated over asix-month period. The results identified multiple distinct source types in regardto molecular weight, hydrophobicity and seasonal variability such as a high mountainwatershed showing humic, larger molecular weight character NOM, andimpounded/conditioned surface water with less humic, smaller molecular weightcharacter NOM. The unique watershed approach used for these studies, involvinginitial evaluation of NOM in discrete water sources--then generalization toseveral broad categories of treatability and chlorine reactivity--has provided avery systematic approach for the City of Boulder in evaluating source watermanagement and treatment options toward the goal of complying with upcomingregulations. Includes 2 references, tables, figures.