This summer we have documented some of the worst water quality we have ever seen on the Talek River, in four years of monitoring, with dissolved oxygen (DO) levels at 40% in the middle of the day, and ammonium levels near 1 mg/L. It has been surprising to see the Talek in such poor condition, even after the relatively high rainfall and flows this season. We have long been interested in the Talek River, and in determining what portion of inputs are due to wildlife versus human sewage. One of Emma's major research interests is human effects on rivers, so we were eager to introduce her to the Talek River. During her and Pat's visit, we traveled from the upper to the lower reaches of the Talek to collect samples on changing water quality and pharmaceutical levels that could indicate the degree of human vs. wildlife impact on the river.
Although we have sampled the middle and lower reaches of the Talek for years, we were incredibly grateful to be invited by the Director of the Mara Conservancy, Brian Heath, to visit the upper-most reaches of the Talek, which are inside the Naboisho Conservancy. He had told us how the river is in generally better condition up there, and we were excited for the opportunity to see it with him and hear his thoughts on the river, as he is such a source of knowledge about the area. As an added bonus, he flew us up there in his plane, covering what would have been about seven bumpy, dusty hours by road in about 10 minutes!
We landed at the airstrip for the Naboisho Conservancy, where we were greeted by the Conservancy rangers and driven to a site on the upper Talek River. Naboisho is a relatively new conservancy, started in 2010, and it is located in a beautiful section of the Mara I had never seen before. The landscape was rolling hills of acacia shrubland, with beautiful open views and lots of wildlife. The location we visited in the upper Talek, near a Naboisho Ranger's Station, was on a lovely stretch of river, lined with smooth, water-shaped rocks. Although the river was quite low, we could see the debris left behind by a huge flood that came through just a few days before our visit. Despite the low water levels, the DO at this site was super-saturated with oxygen, at 130%, indicating high levels of in-stream productivity.
Our next stop was on a small tributary to the upper Talek, the Enesikiria. Here we visited the upper-most hippo pool in this area. This is a great location, because it allows us to investigate the first effects of hippos on the river, and we will likely re-visit it for more sampling in the future. This pool was mostly stagnant, with little water flowing through it, and we could see the impacts of rotting hippo feces on the bottom of the pool. The DO levels here were 1.6%.
This was a great visit, and it convinced us of two things: 1) we should spend more time studying the upper reaches of the Talek River, and 2) we really should buy an airplane to fly to our study sites. Asante sana to Brian for hosting us!
Continuing downstream on the Talek by road, we sampled the Talek above most of the lodges and above and below Talek town. We also had our first, and only!, breakdown of the trip, but fortunately it was a small puncture and easily fixed. DO levels remained fairly high along this stretch, 80-85%, likely due to the high flows that had just come through and flushed out the river. We also sampled another tributary of the Talek, the Olare Orok, at a place fittingly known as "Smelly Crossing." Here DO levels were 27.9%. Although there are a growing number of lodges on this river and its tributary, the Ntiakntiak, it also has the highest density of hippos in the Mara, according to a survey done in 2009 by Erustus Kanga.
So what causes the river to look and smell the way it does-- hippos or people? And how much impact does this small tributary have on the Talek, and the Mara? You can see here an impressively large hippo pool located at the confluence of the Olare Orok and the Talek, with 56 hippos in it, and the plume of dark water emanating from the Olare Orok.
Finally, we reached our last sampling point on the Talek, just before it reaches the Mara River, at Rekero Camp. We have worked with the folks at Rekero Camp for several years now, and they have been incredibly gracious in hosting several of our meters and allowing us to sample the river there. Interestingly, the DO levels here were still quite high, at 84.7%, despite all the inputs coming in from upstream, likely due to the high flows that had just come through the river that week. This emphasizes the critical importance of having sufficient flow levels in a river-- given enough water, rivers have an abundance of natural processes that allow them to breakdown and incorporate a certain amount of inputs. However, when they are robbed of their most important resource, water quality suffers quickly.
After all the traveling and sampling, we were very grateful to the folks at Rekero for inviting us to relax with a cold glass of mango juice. Now this is the way to wrap up a sampling trip!
This was by far the smallest plane I have ever been in, and as a sufferer of motion sickness, I was a little nervous about the flight as we pushed the plane into position for take-off. However, it was a smooth and beautiful flight, it was amazing to see an aerial view of the Mara, and no motion sick bags were necessary.
|Pushing the plane into position for take-off|
|Aerial view of the Mara River|
|The upper Talek inside Naboisho Conservancy|
|High water mark on the upper Talek|
|Investigating a hippo pool on the Enesikiria tributary to the Talek|
|Emma and Pat in front of the plane|
|Breakdown on the Talek-Aitong road|
|Chris measuring water quality on the Olare Orok|
|Pool of 56 hippos at the confluence of Olare Orok and Talek Rivers|
|Chris checking our depth logger in a Talek hippo pool|
|Relaxing at Rekero Camp|