Paving blocks have been widely known as an alternative technology for reducing runoff discharge due to their infiltration performance and capability of retarding the flow. Surface configuration of the different paving blocks types and the openings area play important role in decreasing the runoff velocity. In this study, we investigated the surface runoff velocity on two types of paving blocks layers, and a smooth pavement as comparison. The paving blocks type were rectangular blocks, which have 3.2% openings ratio and hexagonal blocks, which have 6.5% openings ratio. We used a tilted plot covering area of 2 × 6 m, equipped by a rainfall simulator to accommodate the variation of surface slope and rainfall intensity. We measured the velocity by using modification of dye tracer and buoyancy method. The data were then tabulated and graphed based on the paving types and the surface slopes. Generally, the velocity-slope relationship has demonstrated that the increase in surface slope leads to the increase in velocity. In this study, the result showed that slope and rainfall intensity simultaneously influenced the velocity (F = 19.91 > Ftable = 5.14; P < 0.05). However, the findings of this study showed a weak relationship between the changes of surface slope and the changes of runoff velocity on the rectangular blocks (R2 = 0.38). The greater slope did not always invariably lead to the greater runoff velocity. It was likely that there was other predictor variable that was not identified before, and need to be further investigated.

Abstract:There have been various technologies developed to solve the inundation problem that occurs in almost all urban areas. Some of these technologies, such as low impact development (LID), are developed through the concept of source control. The first step of LID practice is to know the runoff behavior on a certain surface of an area, following that, the LID practice is then designed.One of the objectives of LID is to decrease inundation depth on the road. This study aims to learn the profile and behavior of storm water flow along roads before they reach an intersection of a road system in Purwantoro region, Malang City, Indonesia. The study design consisted of field measurements and analytical activities as follows: determination of the independent and dependent variables; field measurements and data collection; simulation of flow profiles with various return periods of rainfall using Hydraulic Simulation Model HEC-RAS ver. 4.1; and verification of the simulation result of flow profiles using observation data. This research concluded that slopes on the branch road and runoff discharge on the main road significantly influenced flow depth at the road intersection. The relationship was expressed by power equations. In contrast, the runoff velocity at the branch road was more influenced by the discharge on the branch road and the main road, and the relationship followed a linear equation. A further study is required to decrease the runoff discharge on the road using LID technology such as concrete block pavement as a replacement for asphalt pavement.

Dealing with flooding in a densely populated flood-prone area poses complex challenges. Almost all residents realize that living in the area is hazardous. However, they choose to stay there. Therefore, flood risk management should be applied in the area. This study aims to: 1) develop facts of the local community in a flood-prone area in decreasing the flood risk while improving well-being through modifying drainage channels used for fish and vegetable farming; 2) evaluate all benefits of drainage investments include the social and economic benefits. The research method consists of a quantitative approach through the distribution of questionnaires and a qualitative approach through in-depth interviews and field surveys. In this study, a concerted community effort was developed as a design parameter. At the same time, the observation parameters include knowledge of the causes of flooding, knowledge of flood risk, community involvement, and government flood control programs. The results showed that the strength of concerted community effort was significantly influenced by the knowledge of flood risk and the local community involvement. This effort can decrease the flood risk by up to 30% and serve direct financial benefits of IDR 48 million in a year.

KEY WORDS: sustainable urban drainage system, low impact development, surface runoff, hydrological model, paving blocks ABSTRACT:Surface roughness has an important role in retarding the runoff velocity. The increase in paving blocks usage, particularly in urban areas, can change the surface roughness of the land. This study investigated the effects of four types of concrete block pavements (CBPs) in retarding the surface runoff velocity. Three design parameters based on CBP properties that considerably influenced the flow retardation were promoted. They were opening ratio (Or), void ratio (Vr) and straight channel ratio (Sr). A tilted plot equipped with a rainfall simulator was used to investigate the influence of surface slope and rainfall intensity to the flow on various CBPs. A modified dye tracing method in view was performed to monitor the surface flow velocity under various rainfall intensities. Flow retardation coefficient (Frd) were calculated based on velocity data on smooth pavement and on CBPs layer measured under the same slope and rainfall intensity. The results showed that flow retardation coefficient increased with an increase in openings ratio, rainfall intensity and surface slope. The relationship between flow retardation coefficient and all design parameters was expressed by a linear regression function. A further study is required to increase the accuracy of the model by modifying the regression function and increasing the variation of design parameters.

Merjosari Village in Malang, which used to be still an agricultural area, has gradually narrowed due to the large number of housing developments by developers. This has an impact on reduced agricultural output, especially chili and tomatoes. Farmers and laborers are unemployed because of the decreasing number of their agricultural lands. The program aims to provide training on the use of mushroom waste in the form of grajen into worm breeding media, program implementation methods by providing outreach programs, training, and providing worm culture facilities and infrastructure for farmers. The results of the program show that farmers and laborers in Merjosari Village can carry out their own cultivation of the lumbricus rubellus worm by utilizing mushroom baglog waste (grajen). The results of the worm cultivation can be sold in the form of worms that can be used as animal feed, birds / poultry, fish, shrimp and so on, the basic ingredients of cosmetics and medicines, and worm feces (vermicompost) used for high-quality organic fertilizers, especially for plants such as flowers and fruit. For farmers and other communities, this program can create self-employment opportunities (entrepreneurship), improve the economy and family welfare, participate in maintaining the balance of ecosystems and the environment.