title: Effects of artificial hypolimnetic oxygenation in a shallow lake. Part 1: phenomenological description and management.
abstract: Artificial oxygenation is a common management technique for lake restoration, but the use of hypolimnetic aeration in shallow basins can have dramatic effects on the dynamics of thermal stratification. This study presents the results of extensive field measurements performed in Lake Serraia (Trentino, Italy) after the installation of a Side Stream Pumping System, whereby oxygen-rich water is injected through 24 jets, uniformly distributed along an octagonal-shaped pipe at approximately 1 m above the sediment floor (10 m in depth). The lake is characterised by an average depth of 7 m, a volume of 3.1 × 10(6) m(3) and a residence time of about one year. Prior to the installation of the pumping system, the undisturbed hypolimnion thickness during summer stratification was relatively small. After the start of oxygen injection (up to 0.5 m(3)/s of oxygen-saturated water), an increase of in-lake temperature over the entire water column was noted with a maximum hypolimnetic temperature increase of up to 9 °C. The analysis of the flow field data and the results of numerical simulations (presented in the companion paper), indicate that the jets were solely responsible for the observed increase in temperature. Moreover, this study shows that modelling efforts are useful to provide guidelines for optimising contrasting needs (e.g., increase in oxygen supply versus jet discharge rate).
authors.affiliation: Department of Civil and Environmental Engineering, University of Trento, via Mesiano 77, 38123 Trento, Italy. marco.toffolon@ing.unitn.it
authors.forename: Marco
authors.initials: M
authors.lastname: Toffolon
authors.forename: Marco
authors.initials: M
authors.lastname: Ragazzi
authors.forename: Maurizio
authors.initials: M
authors.lastname: Righetti
authors.forename: Cristian R
authors.initials: CR
authors.lastname: Teodoru
authors.forename: Marco
authors.initials: M
authors.lastname: Tubino
authors.forename: Chiara
authors.initials: C
authors.lastname: Defrancesco
authors.forename: Sabrina
authors.initials: S
authors.lastname: Pozzi
mesh_terms: D000460:Chlorophyta / Q000254:growth & development; D052918:Environmental Restoration and Remediation; D007558:Italy; D060106:Lakes; D010100:Oxygen; D011157:Population Dynamics; D013696:Temperature; D060753:Water Quality
chemical_list: D010100:Oxygen