Water and heat budgets of a shallow tropical reservoir

Abstract

[1] This study is one of the few attempts to close water and heat budgets in tropical lakes and reservoirs on both daily and monthly time scales. A water budget of Kranji Reservoir is constructed for the year of 2007 using data for water level, reservoir gate operation records, and inflow predicted by a catchment rainfall-runoff model. A heat budget of Kranji Reservoir is also constructed for a field deployment period in 2007 using data for surface radiation fluxes measured by a meteorological station, heat fluxes associated with inflows and outflows, and heat content of the water column measured by thermistors. All the components of the water and heat budgets are accounted for on the basis of a complete data set obtained from field measurements and reliable model predictions, including those that were often neglected in the earlier studies, e.g., advective heat. The water budget of Kranji Reservoir is dominated by the discharge and catchment inflow, which are very sensitive to the variations in precipitation. Analysis of the gate operation records in 2007 shows an appreciable amount of the outflow of Kranji Reservoir was released, especially during storm events. The heat budget reveals that net heat flux of this shallow tropical reservoir is dominated by the net surface radiation fluxes and is also highly responsive to variations in stormflow conditions. It is noted that two critical components in the heat budget are latent heat and inflow advective heat, which equal 83% and 71% of net radiation, respectively.

Thermal structure and variability of a shallow tropical reservoir

“…During this field deployment period, a meteorological station located near M5 was operating (hereafter, referred to as the Met Station). The station recorded air temperature, relative humidity, wind speed and direction, shortwave radiation, and rainfall at 15 min intervals using sensors installed at 1.5 m above water surface (see table 3 of Xing et al [2012] for instrument details). Unfortunately, there was a short gap of about 10 d in the data recorded at the station from 06 May (DOY 126) to 15 May 2007 (DOY 135) due to an equipment malfunction.…”

Robotic mapping of mixing and dispersion of augmented surface water in a drought frequent reservoir

“…Laboratory (e.g., Horsch and Stefan ), field studies of convective flows in side‐arms of reservoirs (Monismith et al ; James and Barko , b ), and numerical modeling work (Horsch and Stefan ; Horsch et al ) have helped identify the mechanisms initiating these downslope gravity flows. More recently, well‐designed studies incorporate multiple thermistor arrays, acoustic Doppler Aurrent Profilers (ADCPs), and meteorological stations to quantify convective flows in lakes or reservoirs (e.g., Xing et al , ; Kirillin et al ; Yang et al ). These studies utilize multiple moored arrays to quantify horizontal convection, but mapping short timescale horizontal variability remains a challenge especially in reservoirs that can undergo rapid changes in horizontal density gradients (e.g., surface wind shear).…”

Investigating summer flow paths in a Dutch agricultural field using high frequency direct measurements

“…We therefore deduced the transient surface watergroundwater (SW-GW) interaction in the ditch by simultaneously solving the water, salinity, and heat balance of the ditch (e.g., Assouline, 1993;Martínez-Alvarez et al, 2011;Xing et al, 2012). The simultaneous solution constrains uncertainty and allows for separation between the shallow and deeper flow paths to the ditch.…”