Biospheric Resonance

Here is an example of how mismanagement of land situated in a watershed led to extreme runoff and a costly flood disaster in December 2007 in South Kona.

A land lessee misguidedly grubbed and graded a parcel of sloping land completely disregarding its natural features such as forestation and streambeds. ( Land mismanagement is widespread in the area, with widespread damage as a consequence. But this particular incident took place upstream of one of the most heavily affected locations, so I’m highlighting it as an example.) When the region was subsequently hit by several hours of extraordinarily heavy rainfall, the land had no capacity left to deal with the enormous amounts of water being shed by the mountainside. Wherever streambeds had been artificially modified in any way, the water had to force new courses on its way down to the ocean. The resulting devastation to both private and municipal property was mindboggling. I’m including some pictures here  taken during and after the deluge to illustrate the situation.

Streambeds and gullies that hadn’t run for 10-20 years were brimming over with a furious mix of water, mud, rocks, and debris within a few hours after it began to rain. Wherever these streambeds had been modified by devegetation, grading, filling, fording, or dumping of weeds or trash, the raging streams were diverted from their proper course and started blindly scouring out new beds. In cases like this the water simply seeks the path of least resistance. Too bad if that happens to be through your orchard, your house, your business premises or the road you drive to work every day. In this particular case the flash floods caused hundreds of thousands of dollars worth of exactly such kinds of damage.

All responsible parties were all too eager to pass the buck, finally calling the floods an “act of God” and washing their hands of any liability. (Why they got away with that is a whole other story, beyond the scope of this article.) Sure, the rains fit that classification perfectly. But the flood damage was 100% man-made and preventable.

If you are developing or managing a parcel of land of any size and want to avoid flood damage to your property and avoid liability for flood damage to the property of others, there are a few simple principles you can follow to minimize the risk.

First of all, find out if your area is classified as a “flood plain“. Possible sources for this information are county and state authorities, USDA/ NRCS, FEMA or Army Corps of Engineers. If it is, you need to find out when it was first classified as such. Generally, the longer ago this classification took place, the more likely it is that the area is a genuine floodplain. More recent reclassifications as such, however, are usually bogus. In that case, your area is more correctly called a watershed.

If you are on a genuine floodplain – an often large, low-lying, flat area bordering on a river, that has been regularly flooded since the dawn of history, there is very little you can do. Such places ought not to be built on. (Unless you build on stilts and move around by boat.) Seasonal cropping or grazing, coppicing and wetland conservaton are more suitable uses for them.

If your area is not a real floodplain but a watershed, keep it that way. Do everything you possibly can (make lots of noise) to stop your area from being reclassified as a floodplain, or two very bad things will happen:

• Your flood insurance premiums will be jacked up through the roof.
• Everyone will start believing that flooding is normal and natural for the area and nobody will want to do anything to correct the situation and prevent flooding.

Here”s how to physically deal with a parcel of land in a watershed area:

• Thoroughly explore the terrain, especially noting all possible past and present streambeds, high, low and steep areas and vegetation types.
• Respect, preserve, and enhance any possible watercourse, whether it has run recently or not. This means first of all don”t grub, grade, fill, or build over it. If it needs to be crossed, a bridge with decent clearance is much safer than a ford.
• If an old streambed is choked up with rocks, logs, trash, or other debris, clean it out.
• Make sure that at least one bank – the one on the side where the most sunlight is coming from – is well vegetated with shrubs and trees so that the actual path of the water is shaded.
• Landscape the upper part of the property with lots of trees / forest, especially if it is a hilltop.
• Build good neighborly relationships, especially with all those upstream from you, and respectfully educate them about the proper watershed management techniques mentioned above.
• If this fails and an upstream neigbor plans to destroy a streambed as part of his development (or has already done so), make it clear you won”t hesitate to sue him or her for any flood damage that may happen to your propertyas a result. If a group of properties stands to be affected, inform the owners of those properties of the risk hanging above their heads and organize a concerted effort to persuade the errant owner to correct the situation.

Again, the vast majority of catastrophic flooding, especially in historically non-floodplain areas is caused by incompetent artificial modification of the landscape and is very preventable. Taking some simple but smart  measures can prevent injury, death, litigation, damage to property, and loss of income.

Have you suffered watershed flood damage in the past? Share your story here! Do you think your property may be at risk? Contact us for a free assessment (via photographs and online geographic information services) to find out how we can help you protect your property with site-appropriate measures.

Tags: eco-hydrology, erosion prevention, flood damage mitigation, flood prevention, land management, property damage, watershed management