Abstract:
Surface water is critical importance to both natural ecosystems and human development.
Lakes are one of the most important resources for human like tourism, irrigation,
drinking etc. Hence lake water quality should be regularly monitored for better
management of the water resources. The aim of the study was to assess the current
physicochemical property and the trophic status of lake Hayq which is located in the
norther part of Ethiopia. Using non probability with judgmental sampling method,
eighteen water samples at six sampling sites were collected in pre wet season (May), wet
(June) and post wet (December) of 2020.Both on site and laboratory analyze of water
quality parameters were conducted. Data analyses used descriptive statix10 to summarize
and analyze of the data, person correlation for relationship, T-test for temporal variation
and, GIS (IDW) interpolation was used for analyzing of spatial variation.
The result shows, the mean value of temperature 27.3C°, turbidity 7.8NTU, SD 1.3m, pH
8.5, EC 908.83μs/cm, TDS 464.8mg/L, TP1.3mg/L, TN 21.84mg/L, DO 7.69mg/l, COD
13.33mg/l, BOD 6.40 mg/L and chlorophyll a 35μg/L. The comparison of result with
fresh water guideline (EPA/USEPA) T, DO, pH and EC with in permissible limits and
TDS, Tur, TP, TN, COD, BOD and CH-a was above permissible limits. The temporal
variation of pollutions was statistically significant (p<0.05) in average dry (may,
December) and wet (July). GIS IDW interpolation shows significant color difference in
spatially variation of parameters along lake shore. Significant correlations were shown
between physicochemical parameters. Trophic State index was TSI 76.7 and TLI 67.5
that indicates higher eutrophic level. The comparison of the result with previous studies
shows increasing of pollution.
Finally, this assessment result indicates high pollutions specially at Rikum logy(sp-5) and
Hayq Estifanos monastery (sp-5) in dry season, whereas irrigation place(sp-3) and
Anqrka river (sp-4) in wet season of lake Hayq. Therefore, providing terrace, buffer zone,
and silt trap are needed to reduce the overflow of pollution. Further study on
mathematical modeling and quantify amount of high nitrogen and phosphorus and design
sustainable management to save and restoring the Lake Hayq.