After washing over land during flooding at high tides, floodwaters carry sediments, debris, nutrients, toxic materials, and bacteria as they recede into nearby waterways. These pollutants can cause direct human and pet health effects and lead to excess nutrient concentrations that contribute to the formation of harmful algae blooms that are a threat to aquatic ecosystems and fisheries. When these blooms decay, they create low oxygen zones that also threaten marine life and aquatic habitats.

Dr. Margaret Mulholland, a biological oceanographer at Old Dominion University, and graduate student Alphonso Macias Tapia developed a pioneering research project to quantify pollution inputs from tidal flooding. Called “Measure the Muck”, their initiative gathered students and volunteers during King Tides, the highest predicted high tides of the year, to collect water samples along the perimeter of the Lafayette River in Norfolk, Virginia. Results indicate that tidal flooding can be a significant source of nutrient enrichment and fecal contamination in local waterways, impacting efforts to restore the Chesapeake Bay and posing a serious public health concern for the large and increasing human populations living in coastal areas.

-- Jackie Siegel, Chrysler Museum Intern




Effects of Tidal Flooding on Estuarine Biogeochemistry: Quantifying Flood-Driven Nitrogen Inputs in an Urban, Lower Chesapeake Bay Sub-Tributary, Alfonso Macías-Tapia, Margaret R. Mulholland, Corday R. Selden, J. Derek Loftis, and Peter W. Bernhardt

News Articles


Measuring the Muck, Jim Morrison


Mulholland Leading Volunteer Effort to "Measure the Muck" in Chesapeake Bay Oct. 27, News @ ODU


1. Water Contamination: Photos, Jim Morrison

2. Water Sampling: Photos, Jim Morrison, Greta Pratt, and Bill Tiernan

3. Water Contamination Effects: Photos, Eduardo Perez Vega and Wolfgang Vogelbein


Unchartered Territory, Broken Ground, Southern Environmental Law Center


Measuring the Muck: Margaret Mulholland on Coastal Flooding and Sea Level Rise, Margaret Mulholland and Shaw Institute