Norma Afiati

Groundwater nutrient inputs into an urbanized tropical estuary system in Indonesia

Groundwater discharge is known to transport nutrients into estuaries at several locations around the world. However, few studies report groundwater-associated nutrient fluxes from tropical developing regions such as Southeast Asia, even though this area shows the strongest human modifications in the coastal zone worldwide. We investigated groundwater nutrient flux into two streams and estuaries (Awur and Sekumbu Bay) in the urban area of Jepara, Indonesia, and its relation with the land usage surrounding the estuaries. We found that average concentrations of NO3, NH4, and PO4 in Jeparas aquifer reached 145μM, 68μM, and 14μM, respectively, and our results indicate that these were mainly originated from untreated sewage, agriculture, and manure input. Approximately 2200tonNyear-1 and 380tonPyear-1 were removed in the soil and aquifer before the nutrients were discharged into the river. The total groundwater discharge into the river and estuary was estimated to 461×103m3d-1, or up to 42% of the river discharge. Discharge of groundwater-associated NO3 (72×103mold-1), NH4 (34×103mold-1), PO4 (5×103mold-1), and additional surface runoff may contribute to eutrophication and a decrease of nearshore surface water quality. Nutrient concentrations in groundwater, river, and coastal seawater in the Jepara region are similar to those found in major urban areas in Southeast Asia, e.g. Manila and Bangkok, even though Jepara has smaller size and population. Thus, our results indicate that medium populated cities with highly modified regional land use can contribute a significant amount of nutrient discharge in the coastal area and should be included in global assessments of nutrient budget calculation.

Coastal People Activity on Mangrove Forest Rehabilitation in Mahakam Estuary

Present condition shows that balance and environmental sustainability of mangrove forests in Mahakam Estuary (Delta Mahakam) area has changed which can result negative effect on people activity of coastal communities. Destruction of mangrove forest is caused by intervention and rapid population growth, especially in coastal areas, which result land use change and excessive utilization of natural resources. This condition can lead to degradation of mangrove forest. In order to rehabilitate mangrove forest, active participation from coastal community is needed. In this regard, this research was carried out in order to assess the perception and participation as well as strategies that can be implemented to improve community participation on mangrove forest rehabilitation. The research was conducted in five villages (Saliki, Salo Palai, Muara Badak Ulu, Muara Badak Ilir and Tanjung Limau), Formulation strategies was carried out using SWOT (Strengths, Weaknesses, Opportunities, Threats) method through Focus Group Discussion which combined with Analytical Hierarchy Process to determine the priority of alternative strategies and policies on mangrove forest rehabilitation. The analysis shows that social factor which influences community’s participation towards the rehabilitation of coastal mangrove forest is perception variable. Strategy which is expected to improve community participation in mangrove rehabilitation activities is carried out by optimizing the strength factor and take advantage from the opportunities (Strengths Opportunities Quadrant Strategy). Based on formulated strategies, it can be obtained four priority alternatives which can be implemented to improve coastal community participation, i.e.: 1) Development of rural participatory for mangrove nursery; 2) Generates positive perception on the strengthening coastal communities about the advantage and functions of mangrove forests; 3) control upon re-vegetation and restoration of coastal areas resources which suffer from degradation and deforestation; and 4) Accelerate the establishment of Guidance Unit Team and Technical Guidance Unit of Mangrove Forest.