| Summary: | The amount of pollutants have caused Code River polluted and reduced
the capacity of the river. In addition, Code is also one of the affected river flow of
Merapi volcano cold lahar in 2010. Eruption have caused massive quantities of
flowing water and sediment to enter the river channels emanating from these
volcano, as well as changed the riverbed substrate. The purposes of this study are:
(1) To analyze the physicochemical quality of Code River water, (2). To compare
the quality of Code River water post-eruption of Merapi 2010 with the condition
before the eruption based on pH, sulfide, and total iron, (3). To analyze the
macrobenthic post-eruption of Merapi Volcano, and then to analyze the effect of
water quality on macrobenthic, (4). To analyze the economic losses and the
perception from the people who use the river for irrigation farming and fishery
cages. Data collection were done by survey method, which the locations were
determined by purposive sampling. It represents the middle part of the River Code
(before the town and the town center), and the downstream of the Code River
(after the town). Water samples were analyzed phisycally and chemically at the
Laboratory. Macrobenthic samples were analyzed by approaches of abundance,
dominance, and diversity index, as well as regression. The results of interview
were analyzed by crosstab to assess public perception and economic losses due to
cold lahar flood.
Study results showed that the parameters of DO, BOD, COD, and nitrate,
did not eligible to the water quality standard Class I in some sites. The turbidity,
phosphate, and sulfide, nearly all sites exceeded the quality standards. Declining
quality of DO, BOD, COD, nitrate, phosphate caused by the waste that goes into
the river, while the decline in the quality of sulfide and turbidity, were caused by
both of waste and the eruption of Merapi. Five genus of macrobenthic found in the
Code River, Chironomous, Simulium, Ephemeroptera, Lymnaea, and Tubifex.
Temperature, water velocity, and DO effected on decreasing diversity and
dominance index of macrobenthic. Code River post-eruption categorized into a
light polluted showed by diversity index = 1.69. Income from agriculture (rice
field) and river-fishery cages after cold lahar flood decreased between Rp
500,0000.00-. 2,000,000.00 / respondent / harvest.
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