Save Hahamongna ... again
Any plan should work with - not against - Hahamongna Watershed Park's natural systems
By Hugh Bowles 05/16/2013
Development plans for Hahamongna Watershed Park took another blow last month. The city of Pasadena transferred a $1 million state grant slated for a new soccer field in the park to John Muir High School. The new project will repair the girls' softball field at the school and incorporate soccer fields. To parents of Muir students and alumni, this is a welcome step; facilities inequities are a persistent issue at the school. The change came from community opposition. It was also revealed that carving up "one of the last remaining natural open spaces in the region" (the city's own description of Hahamongna in its grant application) was not the intended use of the money. But the ongoing tussle over the city's approach to Hahamongna continues.
I used to work in agriculture and recognize our nihilistic tendencies when dealing with natural processes we bend to our advantage. The Hahamongna Park Plan unveiled in 2003 revealed the worst of those instincts. There was a howl of protest and community opposition that triggered the removal of developments on the east side of the park. On the night of the park plan's approval, the city pulled new playing fields, widened roads and parking lots. The cry "Save Hahamongna," while dismissed as coming from those who want no plan, underpins a sense that the park plan should work with - not against - the natural systems. The city's harvest from Hahamongna is water - 40 percent of its annual needs at a quarter of the price of the remainder purchased from the Metropolitan Water District (MWD). The porous alluvial soil structures in the basin are like a sponge. So why does the Hahamongna Park Plan call for so many projects that smother or compact those structures? The key lies in the city's approach to water conservation itself. Those familiar with the area know there is a relay of ponds at the north end of the basin - officially termed spreading basins. Under a 40-year-old agreement, the city pumps water from the underlying Raymond Basin aquifer based on how much water it can get into those ponds each year. The city does this by diverting the stream. The theory is that removing water from the stream and putting it in ponds replenishes the aquifer. Aside from storm events, the city diverts all stream flow up to 20 cubic feet per second (cfs). The new Arroyo Seco Canyon Project, armed with a $3.2 million grant, aims to increase the city's diversion capacity to 30 cfs. This will allow the city to maximize its pumping capacity under the agreement. The project includes converting the JPL parking lot into more spreading basins. The more water in ponds, the more the city can pump from the aquifer. With the water supply corralled, the remainder of the basin is up for grabs. As one staff member said, "There is a lot of land in Hahamongna." There is no need to nurture the sponge; it can be paved, compacted, filled, and the city can still maximize its water extraction. This all sounds great ... until you read a study by Philip Williams and Associates (PWA), a firm of hydrology consultants commissioned in 2000 to provide input to the park plan. PWA cited an earlier study by Converse Consultants West, which found the spreading basins were by "orders of magnitude" less porous than the nearby soils in the basin - they collect silt and heavy maintenance equipment creates compaction. PWA estimated the natural stream could absorb all the water the city currently diverts before it hits the dam; this is water underground, not in ponds. In addition, evidence suggests the best recharge of the aquifer occurs when the stream flows and water is held behind the dam for short periods. None of this is featured in the city's plans.
The pumping agreement gives the city an incentive to kill the stream in Hahamongna - the deader the better; there is no credit for letting the stream flow. But science, attitudes and the evidence suggest the Raymond Basin Management Board and the city should move out of the 1970s. We are not sure how much of the water contained in the ponds simply evaporates, or if it is wise to build more ponds on top of an area that has absorbed the residue of hundreds of cars per day for the last several decades. The natural systems in the basin appear well equipped to aid the city's water allocation.
Hahamongna means "fruitful valley, flowing water." We should acknowledge rather than suppress that. n
Hugh Bowles, a resident of Altadena, has been involved with Hahamongna-related issues since 1994. Contact him at email@example.com.