Lake-TopoCat: A global lake drainage topology and catchment database
Abstract. Lakes and reservoirs are ubiquitous across global landscapes, functioning as the largest repository of liquid surface freshwater, hotspots of carbon cycling, and “sentinels” of climate change. Although typically considered as lentic (hydrologically stationary) environments, lakes are an integral part of global drainage networks. Through perennial and intermittent hydrological connections, lakes often communicate with each other, and these connections actively affect water mass, quality, and energy balances in both lacustrine and fluvial systems. Deciphering how global lakes are hydrologically interconnected, or the so-called “lake drainage topology”, is not only important to lake change attribution, but also increasingly critical to discharge, sediment, and carbon modeling. Despite the proliferation of river hydrography data, lakes remain poorly represented in routing models, partially because there has been no global-scale hydrography dataset tailored to lake drainage basins and networks. Here, we introduce the global Lake drainage Topology and Catchment database, or “Lake-TopoCat”, which reveals detailed lake hydrography information with a careful consideration of possible multifurcation. Lake-TopoCat contains the outlet(s) and catchment(s) of each lake, the inter-connecting reaches among lakes, and a wide suite of attributes depicting lake drainage topology such as upstream and downstream relationship, drainage distance between lakes, and a priori drainage type and connectivity with river networks. Using the HydroLAKES (v1.0) global lake mask, the Lake-TopoCat v1.0 identifies ~1.46 million outlets for ~1.43 million lakes larger than 10 ha and delineates 77.5 million km2 of lake catchments covering 57 % of the Earth’s landmass except Antarctica. The global lakes are interconnected by ~3 million reaches, derived from MERIT Hydro (v1.0.1), stretching a total distance of ~10 million km, ~80 % of which are shorter than 10 km. With such unprecedented lake hydrography details, Lake-TopoCat may facilitate a variety of limnological applications including water quality diagnosis, agriculture and fisheries, lacustrine connectivity monitoring, and integrated lake-river modeling. It is freely accessible at https://doi.org/10.5281/zenodo.7420810 (Sikder et al., 2022).
Md Safat Sikder et al.
Status: final response (author comments only)
- RC1: 'Comment on essd-2022-433', Anonymous Referee #1, 13 Feb 2023
- RC2: 'Comment on essd-2022-433', Anonymous Referee #2, 25 Feb 2023
- AC1: 'Comment on essd-2022-433', Md Safat Sikder, 10 May 2023
Md Safat Sikder et al.
Lake-TopoCat: A global Lake drainage Topology and Catchment database https://doi.org/10.5281/zenodo.7420810
Md Safat Sikder et al.
Viewed (geographical distribution)
Summary Comment – the dataset, Lake-TopoCat will be a valuable contribution to support integrating lakes into hydrological modeling efforts at large scales. The paper is generally well-written. I have some clarifying questions/comments
Paper Organization – this was the paper’s biggest issue, I found that as currently organized a lot of the information ended up being repeated multiple times, while I was often left with questions because the full method description was often spread over multiple sections. I kept writing questions only then to have them answered 10 pages later. I have a few suggestions below which I think would help quite a bit.
Section 2 – I found section 2 quite confusing to read with a lot of unanswered questions that were then answered in sections 3 and 4. I recommend switching the order so explaining how the datasets were developed before the authors present the final datasets, so sections would be: 1, 3, 4, 2, 5. I think the maps and pie charts will be much more effective if readers understand how they were derived first.
Sections 3 and 4 – I would recommend combining sections 3.1 and 3.2 and 4. Having the data inputs with some methods description, separated from section 4, which then further described methods, just created more confusion.
Section 3.3. – This section raised more questions than it answered. I would recommend moving section 3.3 to section 5, which would put all of the validation description in the same place.
Line 17 – change “communicate” to “interact” – the term communicate seems a bit odd here.
Line 34 – the definition of lakes needs to be expanded here. How are the waterbodies referenced distinguished from wetlands, for example, which are barely mentioned.
Line 52 – what does the term “quality-assured” mean here? Please clarify in the text or remove the term.
Line 72 – Change km2 to ha to match the prior dataset descriptions
Figure 4 – add a pie chart of the % distribution, this figure is particularly important since the percents will be count instead of area based.
Figure 6 – Is this showing the line shapefile? The color stretch is a little challenging to see, what are the black areas? Consider changing the black areas to gray like in Figure 7.
322-23 – What does “quality-controlled” mean here? Please clarify in the text or remove the term.
Figure 11b – There is a spelling mistake, change to “Snapped outlet”
Section 5 – how much do you think the DEM quality is impacting the outlet ID accuracy?
Figure 12 – add the R2 and SMAPE like in a and b to panel d
Figure 13b – change the bar graph labels. I understand the current labels represent the source, but at first glance it looks like the accuracy of the NHDPlus versions is what is being presented.