Storm Water Management

Storm Water Management in Monwabisi Park

Introduction

Analyzing storm-water runoff in Monwabisi Park is a complex topic because of the numerous variations in both terrain and ground composition throughout the settlement. In order to understand all aspects of storm-water management, we have analyzed parts of the settlement on both a micro and macro scale. By using this approach, storm-water can be managed first at a micro-level, such as runoff within a cluster or row of housing units, then at a macro-level so that the runoff from each housing cluster can be managed as a group.

All of the data we have collected pertaining to storm-water management is from personal observation.

Current Conditions

Extensive work was done to analyze the current conditions of storm-water management within Monwabisi Park. The results of this analysis are summarized below.  All of the pictures were taken by our team during an extensive tour of the settlement given by a co-researcher.

A lot of the main roads have very large puddles that can last for days. On average, puddles like these can take up to 2 or 3 dry days to completely go away.

Smaller paths are often used, but are also highly prone to flooding. Due to the ground composition and terrain, puddles aren’t confined strictly to low spots.

Hills tend to channel water to lower areas instead of absorb it. In some places, the residents have built small water channels themselves using large stones to try and control the final location of the runoff.

Rocky and hilly terrain becomes slippery when wet, especially when covered with moss. On the other hand, stone is impermeable to water so water flows over it into lower sections. Creating stairs could make walking on stone more manageable and allow for the diversion of water to drainage channels.

The back road drainage system works very well for the portion where it actually exists. The composition of the road seems to successfully channel water down the side curb. Unfortunately, both the curb and the drains are broken so water drains into large puddles at the bottom of the hill.

Much of the water that drains to the back road ends up in a small pond next to the youth center that often overflows. The water flows down at a rapid pace since so much of the park drains here. This location is definitely crucial for the planning process of a storm-water management system.

M section was surprisingly dry. It seems that the sand soaks up a vast majority of the water and because it is elevated higher than any of the other sections, the water runs off the back fairly well. The large areas of stone might also help with water drainage. The worst example of storm-water flooding we could find were the small puddles along the back road as seen in the above left picture.

Even the Indlovu Center experienced a decent amount of flooding around the day care and community center. The water rose extremely fast after a short rain showing that the sand was not extremely permeable here, possibly due to its low location and the composition of the “informal landfill” underneath the sand.

Storm-Water Solutions

There are some important areas in the park that require special consideration with storm-water management. The idea of a v-shaped road has been suggested for the entirety of the park; however, this type of road design would work best if it was implemented only on the back road. The reason for this is due to the topography of the land. The back road is significantly lower than any other area of the park, and thus a lot of storm-water runs to it. By using the v-channel, the back road will effectively act as a large drain and will be able to channel water out of the park. The v-channel is not appropriate for other roads within the park because it would be very difficult to channel the water effectively without unintentionally flooding buildings or houses.  In other areas of Khayelitsha, heavy contamination of storm water makes dealing with it a very important issue. The same applies to many areas of Monwabisi Park. Contaminated storm water must be disposed of as quickly as possible and must be kept away from public facilities and houses. Implementing the v-channel in the back road should be able to move contaminated storm water away from the rest of the park quickly.