I visited 4 out of the 5 locations of this WHS on different days (sometimes doing repeat visits too) in December 2020 and January 2021. Although I had already seen some aflaj in the United Arab Emirates while visiting the Al Ain WHS, the aflaj in northern Oman are a much more elaborate irrigation network which was critical to the development of society and the agricultural economy.

Each falaj gathers water from one or more sources and channels it via a single canal into the area where it is to be used. From the canal, the water is diverted into subcanals into the fields where it sustains the tropical fruit which grows in Oman. Even though today concrete has been used to make the aflaj deeper or to extend the old network, this does not take away the remarkable engineering skills needed in ancient times to construct the aflaj, which supply water on a continuous basis in Oman's arid environment. Recently at Salut (a tentative WHS I'll review later), archaeologists has recently excavated what is believed to be the oldest known falaj out of the approximately 4100 aflaj in Oman today, of which just over 3000 are still functioning.

The water for these aflaj comes from 3 different source types: daudi (which use the underground water table to create water flow through a tunnel to its point of use), ghaili (where the surface water mostly from floods flows into wadis that are dammed and the water is diverted into a channel on one or both sides to its point of use) and aini (which collect the flow from a water spring and channel it to its point of use). The whole construction of any type of falaj required extraordinary spatial accuracy, mathematical precision for water rights to guarantee the distribution of water supply in an equitable manner, as well as divining skills. Some of the wooden tools used as time measuring devices (such as the lamad sundials) or small cairns which were used as fixed objects to take measurements using the movement of the stars were exhibited inside Nizwa Fort.

Aflaj systems are arranged in such a way that agricultural use comes after any personal requirements for people. In the majority of systems, the first water is used for drinking followed by water supplied to the men's bathing area, usually adjacent to a mosque. The women's bathing area follows next then the area for washing dishes and clothes, which is usually just below the women's area. Whenever there was a powerful sheikh or an authority, his house or fort would be placed in close proximity to the men's bathing area, possibly before it or even directly over the falaj itself as at Birkat al Mouz or Rustaq. Finally, the water from the aflaj is used for agriculture.

Especially, at Birkat Al Mouz but also in other aflaj, it was great fun to see children bathing and playing along the aflaj, while their mothers washed their clothes or dishes nearby (even though there are signs inviting people not to). Be careful to avoid embarassing moments when passing by some of the room like structures above the aflaj, as it still isn't uncommon for locals, especially elderly people, to wash themselves there! Nowadays, as Oman changes from an agricultural society to a service and industrial one, the role of the aflaj is changing too. Leisure facilities are being developed around some of them such as Falaj Daris. That said, it was hilarious to spot some washing machines connected to the falaj system of Birkat Al Mouz and it's a real pity that the old mud brick houses have been completely abandoned and have become like a ghost town.

Out of the 5 inscribed aflaj, the only one I didn't visit was Falaj Al Jeela due to its position high in the eastern Hajar mountains towards Wadi Shab (the end of the wadi can be seen from the new bridge on the Sur-Muscat highway, close to the town of Tiwi), which requires a 4x4 vehicle. Having ventured for around 300 km in total on Omani gravel roads and crazy dirt roads, I was tempted to complete all the locations but I had to give up due to quite recent major damage caused by flash floods which would have put me off even if I were driving a 4x4 vehicle.

I visited the inscribed Falaj Al Khatmeen in Birkat Al Mouz several times and at different times of the day. Make sure not to use Falaj Al Khatmeen on Google Maps as it might wrongly direct you away from Birkat Al Mouz through a restricted military airbase area; in general maps.me works fine in Oman. I parked my rental car near the Bayt Ar Rudaydah Castle and even though tourism had just restarted in Oman, immediately several 4x4 drivers rushed to the parking lot to offer their services to Jebel Akhdar. After gently refusing we headed towards the right hand side of the castle where we saw the first UNESCO WHS marker in Arabic, English, French and German. In its shade we observed a group of elderly men playing dominoes and like all the people we met during our visit in Oman, warmly welcomed us and they even offered me a place in the shade to play with them! Even though I was a bit wary because of the current pandemic, I couldn't refuse and with the necessary precautions I have gladly added yet another unforgettable experience of playing a game with locals during my travels.

After that, just behind and above the UNESCO WHS marker, we saw the point where Falaj Al Khatmeen is divided into 3 channels that create a sort of small waterfall and then kept following the falaj beneath it for a couple of hours (even though sometimes there were new walls built over it; it was easy to go round them). If you do this, you'll reach a point where you either literally walk inside or on the falaj at a height of about 10-12 metres or else you back-track a bit and walk beneath it through the date palm fields. We chose the latter, mostly because the water was a bit dirty and we knew about the risk of contracting schistosomiasis, also known as snail fever or bilharzia, which is a disease caused by parasitic flatworms released by infected freshwater snails of which there are plenty in Oman. We did the same when we reached another point where the falaj flows along a beautiful aqueduct with even though we noticed protruding stone-like stairs similar to the stairs of death at Huayna Picchu which give access to the falaj channel above. Apart from the splendid views from the never-ending crumbling ghost towns and towers (Hellat A'Sibani and Burj Al Mukhasir are the most picturesque; morning light is best for photography here) near Birkat Al Mouz, I also recommend driving just outside Birkat Al Mouz to a great panoramic viewpoint of the sea of date palms beneath the crumbling mud houses with the Jebel Akhdar mountains in the background. Head towards the highest broadcasting tower near a small fort-like structure, and make sure to climb up next to the tower as the views are really great. If you were forced to choose only one falaj to visit, I'd definitely recommend this one.

Falaj Al Daris is supposedly the biggest falaj in Oman and is located on the edge of Wadi Al Abydh in Nizwa. The main tributary for Wadi Al Abydh, the source of Falaj Daris, is the great Wadi Tanuf with its dramatic cliffs, which cuts deep into the heart of Jebel Akhdar over 20km away. In a much less natural setting, just off the road, lies a short section of this falaj which has been restored and turned into a little park and picnic area about 7km north of Nizwa where you'll also find the UNESCO WHS marker. Only about 200 meters of the falaj is visible before the channel disappears underground at either end. Indeed it is hard to spend a lot of time here even though contrary to Falaj Al Khatmeen, the water flowing here was crystal clear with plenty of fish providing free pedicure to the locals.

After our free forced extension to our stay in Oman and after driving back to Nizwa and Muscat from Salalah, we visited both inscribed Falaj Al Malki and Falaj Al Muyassar on separate days in December 2020 and January 2021. The village of Imti is near the source for Falaj Al Malki which flows to Izki and the surrounding rural villages or harats and ends in the Arabian Sea at Mahawt. The best bird eye view is obviously from high up from one of the offroad trails of the serrated peaks of Jebel Akhdar and Wadi Halfyn. The town of Izki is mentioned in an inscription in Nineveh from the Assyrian period. There are several Bronze Age tombs from the Hafit period near Izki and the adjacent village of Zukait. The exact GPS coordinates on the UNESCO website lead you to the UNESCO WHS marker which also bears the same coordinates exactly like all the other aflaj markers just in front of a mansion. Near the marker lies a tower-like structure known as Al Swaryn, similar to the great 'ice house' remains found in Ancient Merv, Turkmenistan.

Here, the concrete additions to the falaj have been tiled with limestone. Having ample time, we ventured through the very narrow roads of the different tiny rural villages near Izki following different channels of the falaj. The detailed UNESCO maps clearly show the inscribed areas and turned out to be very useful when comparing them to our GPS maps to explore the area without missing out on the best features we had in mind to explore. The area around scattered farms around the mostly abandoned settlements of Harat Al Yemen and A'Nizwar was like going back in time. Towards the town of Imti we managed to spot one of the most distinctive features of this falaj which is the inverted siphon (top right photo), which enables water from one of the tributaries to cross Wadi Halfyn passing underground rather than over a bridge, whose height would definitely not be sufficient to clear the floodwaters which have a clear impact on the area judging from the surrounding rocks and debris. To find it be on the look out of a huge police station and a small rudimental mosque with golden yellow painted domes. When you find it you'll see a concrete pavement with pebbles and behind it a sort of concrete ramp leading up to a well-like structure. You need to climb it to be able to see the inverted siphon! This was the only spot where the water in this falaj wasn't filthy.

Last but not least, we visited Falaj Al Muyassar, a few kilometers away by car from the tentative WHS of Rustaq Fort. The water for this falaj comes from a well located in Wadi Al Farai. The source water for this wadi is the impressive gorge of Wadi Bani Auf some 10km away. After passing down the town of Rustaq right beneath the Rustaq Fort, the wadi then flows north away from the jagged hills near the oasis of Jamma and onwards to the sea. The sharia of the falaj is close to the small fortress known as Burj Al Mazroui which was built to protect it and which still overlooks a vast oasis full of date palm, papaya, guava and mango, rice fields as well as banana plantations. The UNESCO WHS marker can be found just next to the point where the falaj divides into two channels. Local farmers were directing some of the water towards their fields by relocating wooden boards. Many of the fields watered by the falaj are small so using an ox is still the most ideal way to plough the fields.

We really enjoyed this WHS which provides a great overview of northern Oman and the ancient engineering feat which contributed to convert a desert landscape into a thriving oasis and which is still very much in use. Photos: top left Falaj Daris, top right Falaj Al Malki, bottom left Falaj Al Khatmeen, bottom right Falaj Al Muyassar.