This study investigates the concentration of chlorophyll-a (chl-a) using the data of field observation and MODIS-Aqua imagery. The field observation data were retrieved by using a conventional method and processed using spectrometric analysis. This study covers the coastal and near land areas which have different levels of anthropogenic activity. The results showed that the coastal waters of Semarang with a high level of anthropogenic activity persistently show a concentration of chlorophyll a (chl-a) twice as large as Jepara coastal waters. This comparison value is obtained based on imagery and field data. Meanwhile, the ratio of chl-a field data in each region shows a value of ±5 times greater than the MODIS data. Field observation data shows a higher value than the MODIS-Aqua imagery data. The use of imagery data can be employed as a method of monitoring the eutrophication process on the coast. On the basis of the chlorophyll a classification and field observations, the coastal water of Semarang are classified as eutropic waters and Jepara is categorized as mesotropic category. The classification results will be different if monitoring is carried out using the image data with a location far from the mainland, the Semarang waters are included in the mesotropic category (> 2 mg•m-3) and Jepara is included in the oligotropic water category (< 2 mg•m-3).

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Demak is located on the north coast of Java, precisely in Central Java Province, Indonesia which has many problems related to erosion and shoreline degradation. This study attempts to analyze, identify, and select the materials to build eco-friendly permeable breakwater in Demak. The research was conducted during 2014, consist of several activities, i.e. identified the condition of breakwaters position, materials, and construction, did literature study of identification type breakwaters, study area, sediment, chemical reaction, then reverse design and modification for eco-friendly permeable breakwater. The result is a design of eco-friendly permeable breakwater which used a material of PVC pipe and Bamboo. PVC has excellent chemical resistance, also will increase sedimentation process and accelerate coastal changes towards the sea. Effectiveness level of breakwater made from combination of tire and PVC was 62%, and reveal to be more economical than other general-purpose plastics such as PE, PP, or PS.