Flood Mitigation: Innovative Water Management

The MTDAAT -Ma'a lot Tarshiha Data Acquisition and Analysis Team, which is part of the part of the Park Koren Industrial Management is researching items which may affect our community. One of these items is concerned with Flood Mitigation and Lake Monfort.

The Municipality of Ma'alot-Tarshiha is developing a plan to protect the waters of Lake Monfort. The project will also serve to mitigate the relatively minor, but inconvenient and potentially hazardous, flooding which occurs during the annual rainy season. The project will also help recharge the aquifer.

Urban flooding is due, in part, to the nature of infrastructure. Buildings, roads,sidewalks, parking lots and other surfaces are generally, often unavoidably, constructed with impermeable materials. Rainwater cannot pass through these materials. As a result, it runs off and collects in the streets where it becomes a problem. Just 25 millimeters of rain in an area of 92 square meters equals approximately 2460 liters of runoff (One inch of rain falling in an area of 1000 square feet equals 650 gallons of runoff).

Urban rainwater runoff carries polycyclic aromatic hydrocarbons, gasoline, engine oil, heavy metals and refuse from roads and parking lots. Roof runoff can add synthetic organic compounds to the mix. Gardens and parks are sources of nitrates and phosphorous from fertilizers, and pesticides, herbicides, and fungicides.

Construction has recently been concluded on an eco-waterway, expanded wildlife habitat, and a wetland to purify and keep the waters of the lake clean. However, the lake watershed and the wetland are at risk of damage from the toxic mix of chemicals and heavy metals in the runoff. In the event of extreme rain events which climate change will bring us damage will be more serious, potentially overwhelming the wetland.

Fortunately, there are a number of low-tech changes that can be made to alleviate the problem. The idea is to get out of Mother Nature’s way by replacing existing impermeable surfaces with materials through which water can pass into the soil where pollutants are filtered out.

Fortunately, there are a number of low-tech changes that can be made to alleviate the problem. The idea is to get out of Mother Nature’s way by replacing existing impermeable surfaces with materials through which water can pass into the soil where pollutants are filtered out.

The graphic below illustrates one method to prevent rainwater from collecting in the streets. Water seeps through permeable (porous) filler between paving blocks into sub-surface layers of aggregate (crushed rock and gravel) and soil.

These layers filter the water which is then collected in pipes and conveyed to the lake watershed. Some of the filtered rainwater will seep into deeper soil layers and, ultimately, into the aquifer.

Israel is a water-stressed country in the best of times. The Galil is currently experiencing the fourth year of drought. As of 20 November, the water level of the Kinneret is a mere 55 centimeters above the lowest level ever recorded and falls by approximately 2-3 centimeters each week. At its peak, earlier this year, the level failed to reach the lower red line, though it came close.

Drought also effects the amount of water passing through the watershed to the lake. By diverting filtered runoff that would drain away from the lake, more water will enter the watershed than would otherwise be the case. As a result, less water will need to be pumped to keep the lake at an acceptable level.

Here is the link to a video from 2010 by a local photographer Shlomo Sharvit, showing the water in Lake Monfort at a very low level, and the affect of what happened when rainwater runoff began to pour into the lake.

Furthermore as the elevation of the lake is lower than the city itself, it is our intentions to install a hydro-electric generator to take advantage of the force produced by filtered rainwater flowing though pipes to the lake to provide energy to the eco-waterway pumps.
We are diligently searching for grants from foreign corporations and charitable foundations to finance our projects. It is also our fervent hope that some funding may also be available from the government.

We have asked our local residents to please take photos or videos of the flooding when the rains begin. Since we cannot refit the entire city at one time the citizen photo recording of the scenes of flooding  will help us to choose the best places to begin.
We will soon announce to the local residents where to submit flood reports.
We will install the replacement materials at a few sites, then evaluate the results to see if where we can improve the plan before continuing throughout the city.