I lost my heart at Harties many, many moons ago

I owe Hartbeespoort Dam a great deal.

Once upon a time, many years ago, a sweet young economics reporter joined the staff of the newspaper where I was employed. I was captivated and determined to win her over. Being the die-hard romantic that I am, I invited the sweet young thing to go fishing with me - at Hartbeespoort.

We duly arranged to meet early on a spring Sunday morning. But disaster struck. My friend, who had a boat and was going to accompany us, stayed up carousing the night before and overslept. By the time we arrived to pick up the object of my affections, she had long given up on us (cellphones were still a novelty in those days). All we found was a hand-written note on her gate saying: "If you think I'm going to waste a glorious day like today waiting for you to arrive, you can dream on."

I cursed my tardy friend. I might even have kicked him. There was then nothing for it but to invite the sweet young thing on a proper date. Fortunately, the Harties invitation had broken the ice. She agreed to the proper date and, 18 years of marriage and two gorgeous children later, she is still putting up with me.

Back in the day my friend with the boat and several of us would often go fishing at Harties. We were usually extremely successful at our kurper fishing and often returned home with cooler boxes full of the delicious little fish. That was a long, long time ago. Since then the dam has experienced some well-known problems, and I naturally assumed that the last thing anyone in their right minds would want to do was to eat a fish from Harties.

I was mistaken. It turns out that not only can you eat the fish that comes out of Harties, there is a thriving trade in the things.

Now as scholars of my work will be aware, I am not usually one for singing the praises of civil servants, but even I acknowledge there are many of this breed who are conscientious, proactive individuals working for the common good. I met one by the name of Petrus Venter at the dam last week.

Venter is a Department of Water Affairs director and is the man heading up a departmental/Rand Water initiative called Harties, metsi a me, a programme that is trying to do something about the fact that the dam is what you call hypertrophic - which means it has far too many nutrients in it. The result is a regular explosion in populations of algae and hyacinths that grow like topsy.

To say that Venter is enthusiastic about his work is a gross understatement. To illustrate the extent of the dam's problem, he shared with me a very large number.

"Goodness me," I said, taking notes, "you say you've got 720 million litres of treated sewage entering the dam every year?"

"No, no," said Venter, "that's an average for every day."

In recent years Venter and his team of 140 have removed thousands of tons of hyacinth and millions of litres of slimy, green algae soup. They're rehabilitating shorelines and, by introducing floating wetlands (something Venter is now an internationally recognised pioneer in), aiding the process of natural filtration.

The hyacinth is turned into compost and sold, as are the bottom-feeding carp and barbel. The Harties team now have a dozen fish rangers working on netting and removing these fish which, as they feed, stir up the bottom, raising the levels of nutrients in the water. The fish (190 tons of it and counting) is sold to individuals and entrepreneurs for R5 a kilogram. Workers are incentivised by the amount of fish they produce, how much algae they pull out and how much compost is made.

There are an estimated 900 tons of fish in the dam, which translates into a sustainable harvest of 200 to 300 tons a year. When the numbers of the bad carp and barbel have been reduced, the numbers of the good yellowfish and tilapia (which don't feed on the bottom) will naturally increase. Already the Harties tilapia are getting bigger and the dam is beginning to experience longer periods of clear water than was the case a couple of years ago.

I might go fishing at Harties again one of these days. I may even take the sweet young thing with me.