Dear Ms. Uribe and co-authors

I have read with great interest your paper:

“A SUDS Planning Decision Support Tool to Maximize Ecosystem Services”

My comments are as follows:

1- The paper addresses a very important subject which I have never seen exposed before.

2- When you talk about runoffs, I understand that you refer to water from heavy rains, or it also refers to flooding produced by swollen rivers?

3- On page 3 you say “One of the principal steps of the MCDA methods is the weighting assignation criteria that measure the preferences of alternatives [28]’

I am afraid that I disagree with this statement because criteria weights only measure the relative importance of criteria, and, if they are subjective, they do not participate in the selection of alternatives, as objectives weights do.

4- I find excellent the description to make on page 6 and the references. It is also very good the comments you make on social and environmental needs. I like the maximum and minimo values for evaluation criteria, this is good, and not seen very often. The computation of the priority indexes makes a lot of sense.

5- As I understand, it you consider different types of criteria, as it should be. You also use the GIS, which is a fundamental tool in this kind of scenarios. What I am not sure to understand is how do you quantify each characteristic.

Please, correct a small error in Table 3; it should be grassed swales not gassed swales.

5 - In my opinion, Section 2.5 needs clarification.

6- It appears, in my understanding, that you are considering two main scenarios, which are: Areas of the city that are more prone to flooding, and areas that are most needed for ecosystems, or are adequate for them using different procedures, determining the importance of each one, using indexes, and selecting the areas that maximize both indexes. There is no doubt that this is a complex scenario, and very common in several cities of the world.

I remember a similar project in Canada, but not as complicated like yours, where the solution was the construction of undergrounds tanks, connected with the drainage system, to be used for parks irrigation and street washing.

7- You use the Gurobi Optimizer, that is, Mathematical Programming, and I believe it is the only type of procedure than can solve this problem.

8- I find difficult to find which is the final result, since you analyze, very extensively indeed each area, but I don’t see which, considering all the factors that intervene, is the most preferred area, the second best, etc.

9- I took the liberty of trying to solve this problema using SIMUS, a MCDM method based on Mathematical Programming.

I used your data from Tables 3, 4, and 5 and combined them in an unique matrix of 42 criteria in rows, with the corresponding maximums and minimums, and the five scenarios (Ciudad Verde, Lagos de Torca (El Bosque), Lagos de Torca (Tibabiti), El Reencuento (Calles24 and 26), and El Reencuento (Calle26), as well as physical aspects like Slope, Water table, Infiltration, Area, Wide and Length, in columns, and then working with a 11 x 42 matrix, that is, considering all available data at the same time.

The results is:

Most important area: Tibabiti

Second: Ciudad Verde

Third: El Reencuento, calles 24 and 26

Fourth: El Bosque

Fifth: El Reencuento, calle 26

Most important physical aspect:Slope

Second: Water table

Third: Wide

Forth: Length

Fifth: Area

Sixth: Infiltration

I would very much like to know if this result makes sense to you, or if it does not.

In case you are interested, my calculations are at your disposal.

Thank you for reading my comments

Regards

Nolberto Munier

Of course, you can answer in Spanish if you desire.