The decrease in air quality becomes one of the development impacts that must be controlled deliberately. Planting trees is crucial for reducing the total number of dust and gas pollutants as it can restrain air pollution through absorption and adsorption. This research aimed at (a) determining the most appropriate types of plants for controlling air pollution and (b) developing software to plan the need for Green Open Space (GOS) in the urban city. The criteria of assessment for measuring the ability of a plant to absorb pollutant gas consisted of: (a) the density level of tree-crown, (b) plant combination, (c) thickness level of leaf, (d) the total number of leaves, and (e) plant distance. Meanwhile, the criteria for assessing the ability of the plant to adsorb dust particles comprised: (a) the roughness of leaf surface structure, (b) leaf width, (c) density level of tree-crown, (d) texture of stem skin surface, and (e) density level of the twig. The results of the research demonstrated that plants of Angsana (Pterocarpus indicus), Kihujan (Samanea saman), and Acacia (Acacia auriculiformis) were very appropriate for absorbing pollutant gas. Meanwhile, the good plants for adsorbing dust particles involved Angsana, Kihujan, Acacia, Tanjung (Mimusops elengi), Kersen (Mutingia calabura), Ketapang (Terminalia cattapa), and red Dadap (Erythrina crista-galli) by the level of adsorption ability around 65-75%. The successfully developed software could present suitability between Green Open Space (GOS) calculated manually and the one counted by software.

<p>Surabaya River is very beneficial to Surabaya people as its water becomes the  main source of PDAM (Perusahaan Daerah Air Minum of Regional Water Utility<br />Company). The existing indications on pollution in the flow of Surabaya River due to various activities at its riverbank must not be ignored. Therefore, a study on identifying the distribution of water quality of Surabaya River is required so as to be a reference for formulating control actions to river damage. Identification on water quality distribution was carried out based on the differences of land-use around the left and right sides of river. The research involved the variables of the qualities of river water and waste water thrown into the river, river characteris-tics, and land-use. The results of research  demonstrated that the upstream water quality of Surabaya River was relatively better than the downstream. This statement was proven by the humans’ activities which were more intensively carried out at the downstream area. Numerous land-uses and great number of people living at the riverbank became the phenomena  increasing pressures toward the decreasing quality of river water.</p>

Water treatment in Indonesia still uses coagulant to reduce the contaminant. Therefore, an infiltration gallery is required as the pre-treatment before conventional water treatment conducted. Infiltration gallery is a natural technology for absorbing or filtrating the contaminant. The hydraulic conductivity plays the main role in soil filtration. There are many types of soil with different hydraulic conductivities. In infiltration gallery method it is important to identify the hydraulic conductivity value as the preliminary analysis because it is the important indicator to show the ability of soil to flow the water from one side to other sides when filtrating the contaminant. The slower the conductivity is, the better the quality of the water will be. The method used in this study was the Constant head Permeameter. The result of this study shows that the same type of soil type has different hydraulic conductivities.