Evapotranspiration and crop coefficient for Typha latifolia in constructed wetlands

Abstract

The purpose of this work was to estimate the crop evapotranspiration (ETc) and to determine the crop coefficient (Kc) of Typha latifolia in constructed wetlands. The experiment used two horizontal subsurface flow constructed wetlands (HFCWs) cultivated with T. latifolia. Each HFCW received 50 L of secondary effluent daily, resulting in 3.2 days of nominal hydraulic retention time (disregarding effects of evapotranspiration and precipitation). In order to determine the ETc, water mass balance of the HFCWs was performed. In this analysis, ETc was considered equal to the difference between the inflow (secondary effluent + precipitation) and the outflow. The Kc was calculated using ETc and reference evapotranspiration (ETo) data (Kc = ETc/ETo). The results showed that 7-day average ETc varied dramatically within the range of 4.9–20.0 mm day−1, with a monthly average of 9.85 mm day−1. The mean monthly values of Kc varied from 2.03 to 3.68 (mean: 2.74). ETc is very important with respect to the HFCW water balance because it decreases effluent outflow considerably. Therefore, the findings of this work indicate that water losses caused by evapotranspiration should be considered when designing constructed wetlands.

Estimated seasonal daily evapotranspiration rates for a horizontal subsurface flow constructed wetland

“…The results showed that the evapotranspiration rates varied between 7,35 to 17,31 mm/ day. Queluz et al [17] had similar values in pilot-scale HSSF-CWs, their results were 4,9 to 20 mm/day, nevertheless, they obtained very high results at around 46 mm/day. They did not find the exact reason for this extreme value.…”

The Water Balance of Wet Grassland Sites with Shallow Water Table Conditions in the North-Eastern German Lowlands in Extreme Dry and Wet Years

“…However, the ET 0 values in our study regions are also higher than in southern England. Nonetheless, significantly higher ET a values were found for other vegetation species such as reed, cattail, or silver grass [11,17,[39][40][41][42]. The highest ET 0 value occurs at both sites on 2018-05-29, with 6.8 mm/d.…”

“…For reeds, K c values between 0.73 and 1.51 were found in Hungary [39,40], values between 0.4 and 1.9 in Italy [17], and values between 0.3 and 1.4 in China [12]. K c values of up to 3.15 for reed in the UK [44] or up to 3.68 for Typha latifolia in constructed wetlands in Brazil [42], on the other hand, appear very high and are more likely to be due to other influences, such as a particularly exposed location for advective influences or the small size of the constructed wetlands.…”

Effects of two categorically differing emergent wetland plants on evapotranspiration

“…Evapotranspiration affects the water cycle, extreme weather events, climate, the carbon cycle, regional water balance, cloud formation, agricultural management, drought detection, marine and terrestrial ecosystems (Aguilos et al., 2021; Berkowitz et al., 2020; da Silva et al., 2021; Eichelmann et al., 2018; Fisher et al., 2017; Frédette et al., 2019a; Queluz et al., 2018). Thus, ET is crucial to help answer questions posed by Fisher et al.…”

“…Evapotranspiration affects the water cycle, extreme weather events, climate, the carbon cycle, regional water balance, cloud formation, agricultural management, drought detection, marine and terrestrial ecosystems (Aguilos et al, 2021;Berkowitz et al, 2020;da Silva et al, 2021;Eichelmann et al, 2018;Fisher et al, 2017;Frédette et al, 2019a;Queluz et al, 2018). Thus, ET is crucial to help answer questions posed by Fisher et al (2017), including "How can information on ET be applied to optimize sustainable water allocations, agricultural water use, food production, ecosystem management, and hence water and food security in a changing climate to meet the demands of a growing population?".…”