HYDROLOGICAL AND ECOLOGICAL FUNCTIONS OF WALLO WETLAND HYDROLOGICAL AND ECOLOGICAL FUNCTIONS OF WALLO WETLAND HYDROLOGICAL AND ECOLOGICAL FUNCTIONS OF WALLO WETLAND AND  IMPLICATIONS TO THE DOWN STREAM LAKE CHAMO, ARBA MINCH, ETHIOPIA IMPLICATIONS TO THE DOWN STREAM LAKE CHAMO, ARBA MINCH, ETHIOPIA IMPLICATIONS TO THE DOWN STREAM LAKE CHAMO, ARBA MINCH, ETHIOPIA
Creators: name: EHIT BEKELE BELACHEW
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2017

description: Wetlands are one of the most productive and essential areas with diverse environmental and 
economic benefits. They are also found as threatened habitats in different parts of the world. 
The present study  was aimed to assess the regulatory, filtration and screening role of 
wetlands and valorize for better conservation. A total of six sampling sites were selected from 
Lake Abaya periphery immediately before joining the Wallo wetland and at the outlet of the 
wetland  before joining river Kulfo. The water samples were taken at different strata and 
mixed to make them representative. Sampling was made from  January  to  August,  2016; 
where overflow  was  observed significantly. The  samples were analyzed  for 14  (fourteen) 
selected physicochemical parameters. Standard methods  for sampling, storage and analysis 
were done according to APHA. The study has revealed the existence of significant changes in 
terms of parameters like Dissolved Oxygen, Ionic Concentration,  Heavy Metal  removal, 
nutrient load  and other physical parameters.  The amount of dissolved oxygen has  shown 
improvement by 13.6%  from 5.88  to 7.99ppm after passing through  the wetland.   Removal 
efficiency  of the wetland between inflow and outflow were higher  for  ionic concentrations 
like Electrical Conductivity, Salinity and TDS with 63.1, 40.7 and 54.4 removal percentage 
respectively.  The heavy metals  Mn, Cr,  Cu,  and Fe  analysis  showed a decrease in 
concentration from their inlet by average values of 43.1, 37.2 and 22.1and 12.5 percentages 
respectively. The water samples analyzed for nutrients (T-N and T-P) has also shown a 
decreasing tendency by 40.2 and 33.6% respectively when Lake Abaya water passes through 
the wetland and discharged to river Kulfo. The average water surface temperature recorded 
onsite has decreased from 29.2o
C at Lake Abaya to 25.95o
C at the outlet of the wetland. The 
physical parameters like TSS and Turbidity were found to be high at Lake Abaya and 
significantly decreased at the wetland outlet with 52.9 and 83.3% removals respectively and 
a  slight decrease in  pH.  From the result it can  be concluded  that the wetland  has shown 
remarkable efficiency in terms of screening the incoming suspended and dissolved materials; 
filtering nutrients and heavy metals; and  regulating the temperature and  pH of  the water 
after passing through it. It can be said that overflowed Lake Abaya water which has different 
water chemistry from Lake Chamo has been regulated by the wetland beneath it before 
joining river Kulfo. It is recommended that the role of such wetlands which have paramount 
importance for their hydrological and ecological functions should not be overlooked. Hence, 
conservation efforts to such wetland ecosystems need to be strengthened.